U has an unusual advantage over most letters: a large part of its adjective vocabulary comes from the prefix un-, which can reverse or change the meaning of another word. Certain becomes uncertain, fair becomes unfair, and usual becomes unusual.
But U adjectives are not limited to opposites. Words such as ubiquitous, ultimate, uniform, unique, urban, urgent, useful, and utopian carry meanings of their own. The quick list below focuses on established, useful choices rather than every possible word that can be formed with un-.
Adjectives That Start With U: Quick List
| Adjective | Meaning |
|---|---|
| Ubiquitous | Present or seeming to be present everywhere |
| Ugly | Unpleasant or unattractive in appearance; also unpleasant in other ways |
| Ultimate | Final, greatest, or most important |
| Ulterior | Hidden or not openly stated, especially of a motive |
| Ultramarine | Having a deep blue color |
| Ultramodern | Extremely modern in style or design |
| Ultrasonic | Relating to sound frequencies above normal human hearing |
| Ultraviolet | Relating to electromagnetic radiation beyond violet visible light |
| Umber | Brown or yellowish-brown in color |
| Unable | Not capable of doing something |
| Unabashed | Not embarrassed or ashamed |
| Unacceptable | Not satisfactory or allowable |
| Unadorned | Plain and without decoration |
| Unaffected | Not changed or influenced by something; also natural rather than artificial |
| Unafraid | Not frightened |
| Unanimous | Fully in agreement |
| Unassuming | Modest and not seeking attention |
| Unaware | Not knowing about something |
| Unbearable | Too unpleasant, painful, or difficult to tolerate |
| Unbeatable | Extremely difficult or impossible to defeat |
| Unbiased | Not unfairly favoring one side |
| Unblemished | Free from marks, damage, or faults |
| Unbreakable | Impossible or very difficult to break |
| Uncertain | Not sure, definite, or known |
| Uncomfortable | Causing or experiencing physical or emotional discomfort |
| Uncommon | Not frequently found or occurring |
| Unconditional | Not limited by conditions |
| Unconscious | Not awake or aware |
| Unconventional | Different from accepted or traditional ways |
| Uncooked | Not cooked |
| Uncouth | Rude or lacking good manners |
| Undaunted | Not discouraged or frightened by difficulty |
| Undeniable | Clearly true or impossible to dispute |
| Underage | Below the legally or officially required age |
| Underground | Below the surface of the ground |
| Underlying | Existing beneath the surface or forming a basic cause |
| Underrated | Considered less good or important than deserved |
| Understandable | Easy to understand; also reasonable in the circumstances |
| Understanding | Sympathetic and tolerant toward others |
| Understated | Presented in a restrained or subtle way |
| Undisturbed | Not interrupted, moved, or bothered |
| Undue | Greater or more serious than is reasonable or appropriate |
| Uneasy | Worried, uncomfortable, or not at ease |
| Unequal | Not equal in amount, status, or quality |
| Uneven | Not level, smooth, equal, or regular |
| Unexpected | Not anticipated |
| Unerring | Consistently accurate or not making mistakes |
| Unfair | Not just, equal, or reasonable |
| Unfamiliar | Not known or recognized |
| Unfavorable | Not helpful, positive, or advantageous |
| Unfinished | Not completed |
| Unfit | Not suitable or physically fit for a purpose |
| Unflappable | Remaining calm and self-controlled under pressure |
| Unforgettable | Extremely memorable |
| Unfortunate | Unlucky or regrettable |
| Unfriendly | Not friendly or welcoming |
| Ungainly | Awkward or clumsy in movement or appearance |
| Ungrateful | Not showing gratitude |
| Unhappy | Sad or dissatisfied |
| Unhealthy | Harmful to health or not in good health |
| Uniform | Remaining the same in form, appearance, or character |
| Unified | Brought together as a whole |
| Unilateral | Involving or decided by only one side |
| Unique | Being the only one of its kind or distinctly unlike others |
| United | Joined together for a shared purpose |
| Universal | Applying to or involving everyone or everything in a group |
| Uninterested | Not interested in something |
| Unjust | Not fair or morally right |
| Unkempt | Untidy or not well cared for |
| Unknown | Not known or identified |
| Unlawful | Not permitted by law |
| Unlikely | Not expected to happen or be true |
| Unlimited | Having no fixed limit |
| Unmistakable | So clear or distinctive that it cannot easily be confused |
| Unnecessary | Not needed |
| Unnoticeable | Difficult or impossible to notice |
| Unpleasant | Not enjoyable, attractive, or agreeable |
| Unprecedented | Never having happened or existed before |
| Unpredictable | Difficult or impossible to predict |
| Unqualified | Lacking required qualifications; also complete or without reservation |
| Unreasonable | Not fair, sensible, or based on good reason |
| Unreliable | Not consistently dependable or accurate |
| Unremarkable | Not especially interesting or unusual |
| Unruly | Difficult to control or manage |
| Unsafe | Not safe |
| Unselfish | Concerned with others rather than only yourself |
| Unsettled | Not resolved, stable, or calm |
| Unsightly | Unpleasant to look at |
| Unstable | Not steady, secure, or likely to remain unchanged |
| Unsuitable | Not appropriate for a particular purpose |
| Unsure | Not certain |
| Untidy | Not neat or organized |
| Unusual | Different from what is usual or expected |
| Unwanted | Not wanted or desired |
| Unwelcome | Not wanted or received gladly |
| Unwell | Ill or not feeling healthy |
| Unwieldy | Difficult to carry, handle, or manage |
| Unwilling | Not willing or prepared to do something |
| Unwise | Not showing good judgment |
| Unwitting | Not aware of what you are doing or involved in |
| Unwonted | Unusual or not customary; formal or uncommon |
| Unworkable | Not practical enough to succeed |
| Unworthy | Not deserving respect, attention, or a particular honor |
| Unyielding | Not bending, changing, or giving way |
| Upbeat | Cheerful and optimistic |
| Upcoming | Happening soon |
| Upfront | Honest and direct; also paid or stated in advance |
| Uphill | Sloping upward; also difficult |
| Upright | Vertical; also honest and morally respectable |
| Uproarious | Extremely noisy or causing loud laughter |
| Upscale | Expensive and intended for wealthier customers |
| Upset | Unhappy, worried, or disturbed |
| Upsetting | Causing unhappiness or worry |
| Upstanding | Honest and morally respectable |
| Up-to-date | Including the latest information or developments |
| Upward | Moving or directed toward a higher position |
| Urban | Relating to a city or town |
| Urbane | Polished, confident, and socially sophisticated |
| Urgent | Needing immediate attention or action |
| Ursine | Relating to or resembling a bear; formal or technical |
| Usable | Able to be used effectively |
| Used | Previously owned, handled, or employed |
| Useful | Helping to achieve a purpose |
| Useless | Not useful or effective |
| Usual | Normal or commonly expected |
| Utmost | Greatest or most extreme possible |
| Utopian | Idealized as perfect, often unrealistically |
Common U Adjectives in Everyday English
Many everyday U adjectives are familiar because they describe ability, fairness, safety, usefulness, and ordinary conditions.
Unable
Unable means not capable of doing something.
Maya was unable to attend the meeting because her flight was delayed.
It is commonly followed by to + verb.
The technician was unable to identify the fault.
Uncertain
Uncertain describes something not known, definite, or decided.
The date of the event is still uncertain.
It can also describe a person who is not sure what to think or do.
Ben seemed uncertain about which route to take.
Unfair
Unfair means not just, equal, or reasonable.
It would be unfair to blame one person for the entire mistake.
Unusual
Unusual describes something different from what normally happens or is expected.
The unusually warm weather followed an unusual cold spell.
An unusual thing is not necessarily bad. The adjective simply emphasizes that it is uncommon or different.
Useful
Useful describes something that helps you perform a task, solve a problem, or achieve a purpose.
The map contains useful information about walking routes.
Useless
Useless means unable to perform a useful function or achieve the intended result.
The damaged charger was completely useless.
It can sound harsh when applied directly to a person, so context matters.
Usual
Usual describes something normal, regular, or commonly expected.
We met at our usual table near the window.
Urgent
Urgent describes something requiring immediate or prompt attention.
The doctor received an urgent message from the clinic.
U Adjectives to Describe a Person
Several useful U adjectives describe temperament, behavior, character, confidence, and social manner.
Unassuming
An unassuming person is modest and does not try to attract attention or appear more important than others.
Despite her success, Lena remained quiet and unassuming.
Understanding
An understanding person is sympathetic and willing to consider another person’s circumstances or feelings.
His manager was understanding when the family emergency changed his schedule.
Undaunted
Undaunted describes someone who remains determined despite difficulty, danger, or disappointment.
Undaunted by the first rejection, Priya revised the proposal and tried again.
Unfriendly
An unfriendly person or manner is not warm, welcoming, or pleasant.
The receptionist sounded unfriendly at first but became more helpful later.
Ungrateful
An ungrateful person fails to show appreciation for help, kindness, or something received.
Calling him ungrateful seemed unfair because he had thanked everyone privately.
Because it judges someone’s behavior or attitude, the word can sound strongly critical.
Unselfish
An unselfish person considers other people’s needs and interests rather than focusing only on their own.
Her unselfish decision allowed another student to take the final place.
Upright
When describing character, upright means honest and morally respectable.
The novel presents him as an upright judge who refuses bribes.
It can also describe a vertical physical position.
Urbane
Urbane describes someone polished, confident, and socially sophisticated.
The urbane host moved easily between several different groups of guests.
The word is more formal than friendly or polished.
Upstanding
An upstanding person is considered honest and morally respectable.
She was known as an upstanding member of the community.
U Adjectives for Appearance, Shape, and Physical Condition
Ugly
Ugly most commonly means unpleasant or unattractive in appearance.
An ugly stain had spread across the wall.
It can also describe unpleasant events or behavior.
The disagreement turned ugly after several personal accusations.
When applied to a person’s appearance, the word can be insulting.
Unadorned
Unadorned means plain and without decoration.
The room had simple, unadorned walls.
The word does not necessarily mean unattractive. An unadorned design can be deliberately simple.
Unblemished
Unblemished describes a surface free from marks or imperfections.
The bowl had an unblemished white surface.
It can also be used figuratively for a reputation or record.
She retired with an unblemished professional record.
Uneven
Uneven describes a surface that is not flat, level, or regular.
Take care on the uneven pavement.
It can also describe inconsistent amounts, quality, performance, or distribution.
The team’s performance was uneven throughout the season.
Ungainly
Ungainly describes someone or something awkward in movement, shape, or appearance.
The large bird looked ungainly on the ground but graceful in flight.
Unkempt
Unkempt describes hair, clothing, or someone’s general appearance as untidy or poorly cared for.
After working outside all morning, his hair looked unkempt.
Unsightly
Unsightly means unpleasant to look at.
The temporary fencing was functional but unsightly.
Unwieldy
Unwieldy describes something difficult to carry, move, or manage because of its size, shape, or complexity.
The old camera equipment was heavy and unwieldy.
It can also describe systems or processes that have become difficult to manage.
U Adjectives for Feelings and Reactions
Uneasy
Uneasy means worried, uncomfortable, or unable to relax.
She felt uneasy about leaving the door unlocked.
It can also describe an uncomfortable atmosphere or relationship.
An uneasy silence followed the announcement.
Unhappy
Unhappy means sad, dissatisfied, or displeased.
He was unhappy with the way the complaint had been handled.
Unsure
Unsure describes someone who is not certain about something.
I was unsure whether the shop would still be open.
Upset
Upset describes someone unhappy, worried, angry, or emotionally disturbed.
Nina was upset by the sudden change in plans.
The exact emotion depends on context.
Upsetting
Upsetting describes something that causes emotional distress or worry.
The documentary contains several upsetting scenes.
U Adjectives for Places, Conditions, and Surroundings
Underground
Underground describes something beneath the surface of the ground.
The city has an extensive underground rail network.
It can also describe activities or movements operating secretly or outside official systems.
Undisturbed
Undisturbed describes a place or thing that has not been moved, interrupted, or interfered with.
The birds nested in an undisturbed corner of the reserve.
Urban
Urban means relating to a city or densely built-up area.
The project examines transportation in urban neighborhoods.
Uphill
Uphill describes a slope or direction that rises.
The final section of the trail is steep and uphill.
Figuratively, it can describe something difficult.
Convincing the committee will be an uphill task.
Upscale
Upscale commonly describes places, products, or services that are relatively expensive and aimed at wealthier customers.
The neighborhood has several upscale restaurants and boutiques.
U Adjectives for Ideas, Plans, and Situations
Ubiquitous
Ubiquitous describes something present, found, or encountered almost everywhere.
Smartphones have become ubiquitous in everyday life.
The word does not have to mean literally present in every single place. It often emphasizes that something is extremely widespread or constantly encountered.
Ultimate
Ultimate can mean final in a sequence or process.
Their ultimate destination was a village near the coast.
It can also mean the greatest, most important, or most extreme example.
Winning the championship remained her ultimate ambition.
Underlying
Underlying describes a basic cause, principle, or condition that exists beneath what is immediately visible.
The repair fixed the leak but not the underlying problem.
Undeniable
Undeniable describes something so clear or well supported that it is difficult to dispute.
Her influence on the project was undeniable.
Unprecedented
Unprecedented means never previously known, experienced, or done.
The city experienced unprecedented demand for public transportation.
The word should not simply be used as a stronger synonym for large or important. It specifically refers to the absence of a previous example or precedent.
Unpredictable
Unpredictable describes something whose future behavior or outcome cannot be reliably anticipated.
Mountain weather can be highly unpredictable.
Unreasonable
Unreasonable describes a demand, belief, action, or expectation that is not fair, sensible, or based on good reason.
Asking the team to complete the project overnight would be unreasonable.
Unworkable
Unworkable describes a plan, system, or idea that is not practical enough to succeed.
The original schedule became unworkable after the delivery was delayed.
Up-to-date
Up-to-date describes information, knowledge, equipment, or systems containing or reflecting the latest developments.
Make sure the contact information is up-to-date.
Unable or Unwilling?
These adjectives can lead to the same result, but for very different reasons.
Unable means not capable of doing something.
She was unable to attend because the road was closed.
Unwilling means not prepared or willing to do something.
She was unwilling to attend because she disagreed with the decision.
So:
- unable = cannot do it
- unwilling = does not want or agree to do it
Someone can be perfectly able to do something but still unwilling to do it.
Uninterested or Disinterested?
These words are often confused.
Uninterested means not interested.
He seemed uninterested in the discussion.
Disinterested most usefully means impartial or free from personal advantage in the outcome.
The dispute required a disinterested mediator.
Disinterested is also sometimes used to mean uninterested, but keeping the two meanings separate can make formal writing clearer.
So:
- uninterested spectator = a spectator who has little interest
- disinterested mediator = a mediator without a personal stake in the outcome
Unique or Unusual?
These adjectives both suggest difference, but they are not synonyms.
In its core sense, unique describes something that is the only one of its kind or unlike anything else.
The manuscript contains a unique illustration that appears in no other known copy.
The word is also widely used for something highly distinctive.
Unusual simply means different from what is normal, common, or expected.
We heard an unusual sound coming from the attic.
Something can therefore be unusual without being unique. There may be several examples of the same unusual thing.
Unaware or Unconscious?
Both words involve a lack of awareness, but they are used differently.
Unaware means not knowing about a fact, situation, or event.
She was unaware that the meeting had been moved.
Unconscious most commonly means not awake and aware.
The injured cyclist was briefly unconscious.
It can also describe thoughts, reactions, or actions occurring without deliberate awareness.
He made an unconscious gesture toward the door.
So being unaware of a problem does not mean being physically unconscious.
Two Meanings of Unqualified
Unqualified commonly means lacking the training, skills, or other qualifications required for something.
An unqualified person should not operate the equipment.
But unqualified can also mean complete or given without reservation.
The proposal received her unqualified support.
So the meaning depends heavily on the noun:
- unqualified applicant = someone lacking the necessary qualifications
- unqualified support = complete support without reservation
Useful or Usable?
Useful and usable are related but not interchangeable.
Useful means helpful or able to serve a worthwhile purpose.
The guide contains useful advice for new employees.
Usable means capable of being used.
Only half of the recovered material was still usable.
Something can be usable without being especially useful.
For example, an old computer may still function and therefore be usable, but it may no longer be useful for demanding modern software.
Less Common U Adjectives Worth Knowing
Umber
Umber can be used as an adjective for a medium to dark brown or yellowish-brown color.
The artist added umber shadows beneath the trees.
The word is also commonly used as a noun for the pigment or color.
Ulterior
Ulterior usually describes a motive, purpose, or reason that is hidden rather than openly stated.
She wondered whether he had an ulterior motive for offering to help.
Ulterior motive is by far the most familiar combination in everyday English.
Unabashed
Unabashed describes someone who is not embarrassed, ashamed, or self-conscious about something.
He is an unabashed admirer of old detective films.
Unerring
Unerring means consistently accurate or not making mistakes.
She has an unerring ability to notice inconsistencies in a report.
The word is relatively formal and often appears before nouns such as judgment, instinct, accuracy, or aim.
Unflappable
Unflappable describes someone who remains calm and self-controlled even in difficult or surprising situations.
The unflappable receptionist handled the confusion without raising her voice.
Unwonted
Unwonted is a formal and uncommon adjective meaning unusual or not customary for a particular person or situation.
He greeted the announcement with unwonted enthusiasm.
It is much less common than unusual.
Ursine
Ursine is a formal or technical adjective meaning relating to or resembling a bear.
The animal’s broad head gave it a slightly ursine appearance.
Utopian
Utopian describes an imagined system, plan, or society considered ideally perfect, often in a way that may be unrealistic.
The proposal was criticized as an attractive but utopian vision.
For adjectives beginning with every letter of the alphabet, see the A–Z list of adjectives with meanings.
Explore Adjectives by Letter
A | B | C | D | E | F | G | H | I | J | K | L | M
N | O | P | Q | R | S | T | U | V | W | X | Y | Z
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