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B2 noun /ˈjuː.sɪdʒ/

Usage

使用
Meaning
the action of using something; the way in which words are used in a language
Example
The dictionary explains the correct usage of difficult words.
词典解释了难词的正确用法。
C1 adjective /ʌnˈduː/

Undue

过度的; 不适当的; 超过必要或适当的
Meaning
excessive; inappropriate; more than is necessary or proper
Example
The teacher complained about undue pressure from parents.
老师抱怨家长施加的过度压力。
B2 adjective /ʌnˈwaɪz/

unwise

不明智
Meaning
Showing poor judgment; not sensible or prudent.
Example
It would be unwise to invest all your money in one company.
把所有的钱都投入一家公司的做法不明智。
C1 adjective /ˌʌnbɪˈliːvɪŋ/

unbelieving

不相信的
Meaning
Not willing or able to believe; skeptical or doubtful
Example
She gave him an unbelieving look when he claimed to have met a celebrity.
当他声称见过一位名人时，她给了他一个不相信的眼神。
C1 adjective /ˌʌn.əˈdʌl.tə.reɪ.tɪd/

Unadulterated

纯净的
Meaning
not mixed or diluted with any different or extra elements; pure
Example
She felt unadulterated joy when she heard the news.
当她听到这个消息时，她感到纯净的快乐。
B2 adjective /ʌnˈɡreɪt.fəl/

Ungrateful

忘恩负义
Meaning
not feeling or showing thanks for something done or given; not appreciating kindness
Example
She felt he was ungrateful for all the help she had given him.
她觉得他对她给予的所有帮助都忘恩负义。
C2 noun /ˈʌm.brə/

Umbra

完全的阴影，太阳黑子的黑暗中心
Meaning
the fully shaded inner region of a shadow cast by an opaque object; the dark center of a sunspot
Example
During the eclipse, we stood in the moon's umbra.
在日食期间，我们站在月亮的本影中。
C1 adjective /ˌʌnrɪˈfaɪnd/

unrefined

未精炼的
Meaning
not processed or purified; lacking polish or sophistication
Example
The unrefined oil must be processed before it can be used as fuel.
未精炼的石油在用作燃料之前必须进行加工。
C2 noun /ʌnˈkloʊðɪŋ/

unclothing

脱衣
Meaning
the act or process of removing clothing
Example
The child quickly ran inside for unclothing after playing in the mud.
孩子在泥地玩耍后迅速跑进去脱衣。
B2 verb /ɜːrdʒ/

urge

催促
Meaning
to strongly encourage or try to persuade someone to do something
Example
Doctors urge patients to exercise regularly.
医生鼓励病人定期锻炼。
B2 adjective /ˌʌnkənˈvɛnʃənl/

unconventional

非传统的
Meaning
not based on or conforming to what is generally done or believed
Example
Her unconventional approach to teaching inspired her students to think creatively.
她非传统的教学方法激发了学生的创造性思维。
B2 adjective /ˌʌndərˈlaɪɪŋ/

underlying

基本的
Meaning
basic or hidden but important; forming the foundation of something
Example
The underlying reason for the conflict was never addressed.
冲突的根本原因从未得到解决。
C1 adjective /ʌnˈdɔːntɪd/

Undaunted

无畏的; 勇敢的; 不屈的;
Meaning
not intimidated or discouraged by difficulty, danger, or disappointment
Example
Despite the setbacks, she remained undaunted in pursuing her goals.
尽管遇到挫折，她在追求目标时依然无畏。
C2 adjective /ʌnˈblʌʃɪŋ/

Unblushing

厚颜无耻的; 放肆的
Meaning
showing no shame or embarrassment; boldly shameless
Example
He told the unblushing lie without any hesitation.
他毫不犹豫地说了那个无耻的谎言。
A2 adjective /ʌnˈhæp.i/

Unhappy

不快乐; 难过
Meaning
not happy; feeling sad or displeased; unfortunate or undesirable
Example
He was unhappy with the results of his exam.
他对考试结果感到不满。
B2 verb /ˌʌndərˈɛstɪmeɪt/

underestimate

低估
Meaning
To judge something as less important or smaller than it really is.
Example
Never underestimate the power of teamwork.
永远不要低估团队合作的力量。
C1 noun /ˈʌndərˌɡɑːrmənt/

undergarment

内衣
Meaning
a piece of clothing worn under outer clothes, usually next to the skin
Example
He bought new undergarments for the wedding.
他为婚礼买了新的内衣。
C2 adjective /ˈʌndjʊleɪtɪŋ/

undulating

波动的
Meaning
Having a smoothly rising and falling form or motion like waves.
Example
We drove through undulating hills.
我们驱车穿过起伏的山丘。
B2 noun /ˈʌpˌkiːp/

up-keep

维护
Meaning
The process or cost of maintaining something in good condition.
Example
The upkeep of the old house is very expensive.
老房子的维护非常昂贵。
B1 adjective /ˌʌnˈɪntrəstɪŋ/

uninteresting

无趣的
Meaning
not holding attention or curiosity; boring
Example
The lecture was uninteresting and difficult to stay focused on.
这次讲座很无趣，很难集中注意力。
B2 noun ˌjuːtɪlaɪˈzeɪʃən

utilization

利用
Meaning
The action of making practical and effective use of something.
Example
Increased plastic utilization calls for better waste management.
塑料的使用增加要求更好的废物管理。
B2 noun ˈjuːnəti

unity

团结
Meaning
The state of being united or joined as a whole.
Example
Unity among people led to victory.
人们之间的团结带来了胜利。
B2 adjective /ˌʌn.kəʊˈɒp.ər.ə.tɪv/

uncooperative

不合作的
Meaning
not willing to help or work with others; unhelpful
Example
The witness was uncooperative and refused to answer questions.
证人不合作，拒绝回答问题。
B2 adjective /ʌnhaɪˈdʒiːnɪk/

Unhygienic

不卫生的；缺乏适当的卫生
Meaning
not clean; lacking proper sanitation
Example
The restaurant was closed due to unhygienic conditions in the kitchen.
由于厨房不卫生的条件，餐厅被关闭。
C1 adjective /ʌnˈtaɪərɪŋ/

Untiring

不知疲倦的; 坚持不懈的; 永不止步的
Meaning
continuing without stopping; persistent; tireless
Example
Her untiring efforts finally led to success.
她的不知疲倦的努力最终带来了成功。
B2 verb ˈjuːnɪfaɪ

unify

统一
Meaning
To make or become united, uniform, or whole; to bring together into a single unit.
Example
Adolescents unify with peers for social acceptance.
青少年为了社会接纳与同伴统一。
C1 adjective /ʌnˈsəʊʃəl/

unsocial

不合群的
Meaning
not enjoying the company of others; avoiding social interaction; contrary to social norms
Example
He prefers unsocial hours so he can work alone without interruptions.
他更喜欢不合群的工作时间来独自工作。
B2 adjective /ˌʌndɪˈveləpt/

Undeveloped

未开发的; 未成熟的; 原始的
Meaning
not yet developed; immature or primitive
Example
The undeveloped land was later turned into a park.
未开发的土地后来被改建成了一个公园。
B1 adjective /ʌnˈlaɪk/

Unlike

不同的; 不相似的
Meaning
different from; not similar to
Example
Unlike his brother, he prefers quiet activities.
与他哥哥不同，他喜欢安静的活动。
A2 adjective /ˈjuːs.ləs/

Useless

无用
Meaning
having no beneficial purpose; not useful
Example
This broken computer is completely useless.
这个坏掉的电脑完全是无用的。
B1 verb /ˈʌpˌɡreɪd/

upgrade

升级
Meaning
to raise something to a higher standard, improve
Example
We decided to upgrade the software to the latest version.
我们决定将软件升级到最新版本。
C2 adjective /ʌnəˈpiːzd/

unappeased

不平息的
Meaning
Not satisfied or calmed; still feeling discontent or anger
Example
Despite the apology, she remained unappeased.
尽管道歉，她仍然不平息的。
C1 adjective /ˌʌnkɒnstɪˈtuːʃənəl/

Unconstitutional

违宪的
Meaning
not in accordance with a political constitution; violating constitutional principles
Example
The court declared the new law unconstitutional.
法院宣布这项新法律违宪。
B2 adjective /ʌnəˈfreɪd/

unafraid

无畏
Meaning
Not feeling fear; brave or courageous
Example
She walked into the dark room, unafraid of what might be inside.
她走进黑暗的房间，无畏里面可能有什么。
C2 noun /ˈʌndərlɪŋ/

underling

下属
Meaning
a person of low rank or importance; a subordinate
Example
The manager ordered his underlings to finish the task quickly.
经理命令他的下属快速完成任务。
C1 adjective /ʌnˈkɛmpt/

unkempt

邋遢
Meaning
Having an untidy or disheveled appearance.
Example
He looked unkempt after sleeping outdoors all night.
他睡了一整晚露天后，看起来邋遢。
C1 adjective /ʌnˈspiːkəbl/

unspeakable

难以形容
Meaning
too bad or shocking to be expressed in words
Example
The survivors endured unspeakable horrors during the war.
幸存者在战争中忍受了难以形容的恐怖。
C1 adjective ʌnˈtʃɑːtɪd

uncharted

未标记
Meaning
Not mapped or surveyed; unknown or unexplored.
Example
The mission aimed to explore uncharted areas of the planet.
该任务旨在探索星球上未标记的区域。
C1 adjective /ˌʌnɪˈkwɪvəkəl/

unequivocal

明确
Meaning
Leaving no doubt; clear and unambiguous
Example
She gave an unequivocal answer to the question.
她对问题给出了明确的回答。
A2 adjective /ʌnˈhel.θi/

Unhealthy

不健康的; 有害的
Meaning
harmful to health; not in good health; detrimental to well-being
Example
Eating too much fast food is unhealthy for your body.
吃太多快餐对你的身体不健康。
B2 adjective /ˌjuːnɪˈvɜːrsəl/

Universal

普遍的
Meaning
applicable to all cases; existing everywhere
Example
Music is a universal language that everyone understands.
音乐是一种普遍的语言，人人都能理解。
C2 adjective /ˌʌnɪkˈsɛpʃənəbl/

unexceptionable

无可指摘
Meaning
Not open to objection; acceptable and unobjectionable
Example
His behavior was unexceptionable throughout the event.
他的行为在整个事件中都是无可指摘的。
A2 noun /ˈʌndərweər/

underwear

内衣
Meaning
Clothing worn beneath outer clothes, typically next to the skin.
Example
He bought new underwear for the trip.
他为旅行买了新的内衣。
B1 noun /ˈjuːnɪvɜːrs/

Universe

宇宙
Meaning
all existing matter and space; the cosmos
Example
Scientists study the universe to understand its mysteries.
科学家研究宇宙，以理解它的奥秘。
C1 noun /ˈʌp.ʃɒt/

Upshot

结果; 结论
Meaning
the final result or outcome of a series of events; conclusion
Example
The upshot of the meeting was a decision to postpone the project.
会议的结果是决定推迟项目。
B2 adverb /ʌnˈsɜːrtənli/

uncertainly

不确定地
Meaning
in a way that shows doubt or lack of certainty
Example
She glanced uncertainly at the complicated instructions.
她不确定地看着复杂的说明。
C1 adjective /ˌʌnrɪˈkwaɪtɪd/

unrequited

Meaning
Not returned or reciprocated, especially in the context of love or affection.
Example
He suffered from unrequited love for years.
C1 adjective /ʌnˈkleɪmd/

Unclaimed

未认领的; 未要求的; 被遗弃或无主的
Meaning
not claimed by anyone; not demanded or requested; abandoned or ownerless
Example
The unclaimed luggage was stored in the airport's lost property department.
未认领的行李被存放在机场的失物招领处。
B2 adjective /ˌʌnɪnˈfɔːrmd/

uninformed

不了解情况的
Meaning
lacking knowledge or awareness about a particular subject; not educated or informed
Example
The decision was made by an uninformed committee.
这个决定是由一个不了解情况的委员会做出的。
A2 noun /ˈjuːnɪt/

unit

单元
Meaning
an individual thing or person regarded as a single and complete entity
Example
Each unit in the production line is carefully tested.
生产线上的每个单元都经过仔细测试。
B2 adjective /ʌnˈrɪəl/

unreal

不真实的
Meaning
not real or not based on reality; exaggerated or imaginary
Example
The experience felt unreal after the sudden news.
突如其来的消息后，这种经历感觉不真实。
B2 adverb /ˈʌltəmətli/

ultimately

最终
Meaning
in the end, after everything else
Example
Ultimately, we decided to go ahead with the project.
最终，我们决定继续推进该项目。
C1 adjective /ʌnˈtɛnəbl/

untenable

无法维持
Meaning
not able to be maintained or defended against attack or objection
Example
The politician resigned when his position became untenable.
政治家在他的立场变得无法维持时辞职。
C1 adjective ʌnˈskruːpjʊləs

unscrupulous

不道德的
Meaning
Having or showing no moral principles; not honest or fair.
Example
Unscrupulous peers can lead adolescents to delinquency.
不道德的同龄人可能会导致青少年犯罪。
C2 noun /juːˈkeɪs/

ukase

法令
Meaning
An authoritative decree or order, especially one issued by a sovereign or government.
Example
The czar issued a ukase restricting the freedom of the press.
沙皇发布了一项限制新闻自由的法令。
C1 noun /ˌʌnbɪˈliːf/

Unbelief

不信
Meaning
lack of religious belief; skepticism or doubt
Example
His unbelief in the supernatural made him a skeptic.
他对超自然的怀疑使他成为了一个怀疑者。
A2 noun /ˌʌpˈsteəz/

Upstairs

楼上
Meaning
on or to an upper floor of a building; the upper floor or floors
Example
She went upstairs to her bedroom to rest.
她上楼去她的卧室休息。
C1 verb /ˌʌn.dəˈtʃɑːrdʒ/

undercharge

收取较少费用
Meaning
To charge less than the correct or fair amount.
Example
The shopkeeper accidentally undercharged me for the groceries.
店主不小心少收了我购买食品的钱。
B2 adjective /ʌnˈhɜːrt/

unhurt

毫发无损
Meaning
Not injured or harmed.
Example
She walked away from the accident unhurt.
她在事故中毫发无损。
C2 adjective /ˌʌnprəˈpɪʃəs/

unpropitious

不利
Meaning
Not giving or indicating a good chance of success; unfavorable.
Example
The team began their journey under unpropitious weather conditions.
团队在不利的天气条件下开始了他们的旅程。
C1 adjective /ˌʌnsəˈfɪstɪˌkeɪtɪd/

unsophisticated

不复杂
Meaning
Lacking worldly experience, refinement, or complexity.
Example
The villagers led an unsophisticated but happy life.
村民过着简单而幸福的生活。
B2 noun /ʌnˈkaɪndnəs/

unkindness

不友善
Meaning
lack of kindness; cruel or inconsiderate behavior
Example
His unkindness hurt her feelings deeply.
他的不友善深深伤害了她的感情。
B2 adverb juːˈnæn.ɪ.məs.li

unanimously

一致通过
Meaning
With the agreement of all people involved; without opposition.
Example
The proposal was unanimously accepted.
提案得到了全体一致通过。
A1 interjection /ʌ/

uh

呃
Meaning
a sound people make when they hesitate or are unsure what to say next.
Example
Uh, I’m not sure if that’s the right answer.
呃，我不确定这是不是正确的答案。
C2 adjective /ˌʌltrəˈmʌndeɪn/

ultramundane

超凡
Meaning
Relating to things beyond the physical world; supernatural or transcendental.
Example
Philosophers often discuss ultramundane realities beyond human perception.
哲学家们常常讨论超越人类感知的超凡现实。
B2 adjective /ʌnˈɪndʒərd/

uninjured

未受伤
Meaning
Without injury; not physically harmed.
Example
All the passengers were rescued uninjured.
所有乘客都没有受伤并被救援。
C1 adjective ˌʌn.pəˈtɜːbd

unperturbed

不为某事烦恼或困扰；冷静且镇定
Meaning
Not worried or disturbed by something; calm and composed.
Example
She remained unperturbed despite the challenges.
尽管有挑战，她依然保持冷静。
B2 adjective /ʌnˈfeɪv(ə)rəbəl/

unfavorable

不利
Meaning
not beneficial or advantageous; showing disapproval or opposition
Example
The proposal received an unfavorable response from the committee.
提案收到了委员会的负面回应。
A2 noun /ʌmˈbrɛlə/

umbrella

伞
Meaning
A device used for protection against rain or sun, typically consisting of a collapsible canopy mounted on a central rod.
Example
She opened her umbrella as it started to rain.
下雨时她打开了她的伞。
B2 adjective /ʌn.rɪˈleɪ.tɪd/

Unrelated

无关的; 不相关
Meaning
having no connection or relationship; not connected by family ties
Example
The two incidents were completely unrelated to each other.
这两个事件完全无关。
A1 preposition /ˈʌndər/

under

下
Meaning
in or to a lower position than something
Example
The cat is under the table.
猫在桌子下面。
B2 adverb /ʌnˈnesəserəli/

Unnecessarily

不必要地
Meaning
to a greater extent than is needed; without necessity
Example
Don't worry unnecessarily about the exam.
不要为考试不必要地担心。
C1 adjective /ʌnˈhoʊli/

Unholy

亵渎的; 罪恶的; 亵渎的
Meaning
wicked; sinful; profane
Example
The unholy alliance between the two companies caused public outrage.
这两家公司之间的不圣洁联盟引发了公众愤怒。
C2 adjective /ʌnˈfeɪnd/

unfeigned

真诚
Meaning
genuine; not pretended or insincere
Example
She expressed unfeigned joy at her friend's success.
她在朋友的成功上表达了真诚的喜悦。
C2 verb /ˌʌn.dɪˈsiːv/

undeceive

解惑
Meaning
To free someone from a misconception or false belief.
Example
She tried to undeceive him about the false rumors.
她试图让他摆脱这些错误的谣言。
B2 adjective /ʌnˈlɪmɪtɪd/

unlimited

无限
Meaning
without any limits or restrictions
Example
The internet plan offers unlimited data for the whole month.
该互联网计划提供整个一个月的无限数据。
C2 adjective /ʌnˈɡeɪnli/

ungainly

笨拙
Meaning
Awkward, clumsy, or lacking grace in movement or appearance.
Example
The tall boy moved in an ungainly manner.
那个高个男孩以笨拙的方式走动。
C1 noun /ˈʌndərdɒɡ/

underdog

逆袭者
Meaning
a competitor thought to have little chance of winning; a weaker party in a contest
Example
The underdog team surprised everyone by winning the championship.
逆袭者队伍通过赢得锦标赛让所有人都惊讶。
C2 verb /ʌnˈkloʊð/

unclothe

脱衣; 脱掉衣服
Meaning
to remove clothing from someone or something
Example
The nurse helped unclothe the patient for the examination.
护士帮助病人脱衣进行检查。
C1 adjective /ʌnˈkwes.tʃən.ə.bl̩/

Unquestionable

无可争议的; 确定的
Meaning
not able to be disputed or doubted; certain and beyond doubt
Example
Her honesty and integrity are unquestionable qualities.
她的诚实和正直是无可争议的品质。
C1 adjective /ˈʌndərhænd/

underhand

阴险
Meaning
done secretly and dishonestly; deceitful
Example
The politician was accused of using underhand tactics to win the election.
那位政治家被指控使用阴险的手段赢得选举。
C1 adjective /ˌʌnəˈteɪnəbl/

unattainable

无法实现的
Meaning
impossible to achieve, reach, or accomplish
Example
For many, becoming a professional athlete remains an unattainable dream.
对许多人来说，成为职业运动员仍然是一个无法实现的梦想。
C1 adjective /ʌnˈsɪvəlaɪzd/

Uncivilized

未开化的; 野蛮的;
Meaning
not developed in terms of civilization; lacking social organization and culture; barbarous
Example
The explorers encountered an uncivilized tribe deep in the Amazon rainforest.
探险者在亚马逊雨林深处遇到一个未开化的部落。
B2 adjective /ˈʌt.ɚ/

Utter

完全的; 绝对的; 全部的
Meaning
complete; absolute; total
Example
The movie was an utter disaster at the box office.
这部电影在票房上完全失败了。
B1 adverb /ʌnˈjuːʒuəli/

unusually

异常地
Meaning
in a way that is not typical or expected; to an uncommon degree
Example
It was unusually cold for this time of year.
对一年中的这个时候来说，天气异常寒冷。
C1 noun /ˈʌlsər/

ulcer

Meaning
a sore on the skin or a mucous membrane that does not heal easily
Example
The doctor prescribed medicine to treat the stomach ulcer.
C1 adjective /ʌnˈsiːmli/

unseemly

不得体
Meaning
Not proper or appropriate in behavior or appearance; unbecoming.
Example
His unseemly remarks embarrassed everyone at the dinner table.
他不得体的言论让晚餐桌上的每个人都感到尴尬。
B2 adjective /ʌnˈtʃeɪndʒɪŋ/

unchanging

不变的
Meaning
remaining the same over time; not changing
Example
Her love for her family was unchanging throughout the years.
她对家人的爱多年来始终不变。
B1 adjective /ˌʌnsəkˈsesfl/

Unsuccessful

失败的; 没有成功的;
Meaning
not achieving desired aims or results; failing to accomplish a purpose
Example
His unsuccessful attempt to climb the mountain left him disappointed.
他未能成功登上山顶，感到失望。
B2 verb /ʌnˈfəʊld/

unfold

展开或打开
Meaning
to open or spread out something that was folded; to gradually reveal or develop
Example
She unfolded the letter carefully.
她小心地展开了信件。
B2 adverb /ʌnˈdaʊtɪdli/

undoubtedly

毫无疑问
Meaning
without a doubt, certainly
Example
He is undoubtedly the best player on the team.
他毫无疑问是队里最好的球员。
B2 adjective /ˌʌnəˈfɪʃ.əl/

Unofficial

非官方的
Meaning
not officially authorized or confirmed; informal
Example
The unofficial results showed a close race.
非官方的结果显示出一场激烈的比赛。
B1 adjective /ʌnˈkaɪnd/

Unkind

残忍; 不友好
Meaning
cruel; not nice or caring toward others
Example
It was unkind of him to make fun of her appearance.
他取笑她的外貌，真是太不友善了。
C2 adjective /ˈʌŋk.tʃu.əs/

unctuous

阿谀奉承
Meaning
Excessively flattering or ingratiating; oily in texture.
Example
His unctuous tone made everyone uncomfortable.
他那种阿谀奉承的语气让每个人都感到不舒服。
B2 adjective /ʌnˈwel.kəm/

Unwelcome

不受欢迎的; 不想要的; 不邀请的
Meaning
not wanted or accepted; not invited or pleasant
Example
The unwelcome news ruined their vacation plans.
不受欢迎的消息破坏了他们的度假计划。
C2 adjective /ʌkˈsɔːriəs/

uxorious

过度宠爱妻子
Meaning
excessively fond of or submissive to one's wife
Example
He was so uxorious that he agreed with everything his wife said.
他是如此的宠爱妻子，以至于同意了妻子说的每一件事。
A1 noun /ˌjuːnɪˈvɜːrsɪti/

university

大学
Meaning
an institution of higher education and research, which grants academic degrees
Example
She is studying law at the university.
她在大学学习法律。
B1 verb /juˈnaɪt/

unite

联合
Meaning
to join together or combine; to bring people or things together
Example
The crisis helped unite the community.
危机帮助团结了社区。
C1 adjective /ˌʌnəˈsjuːmɪŋ/

unassuming

谦虚
Meaning
Not pretentious or arrogant; modest.
Example
Despite his success, he remained unassuming and humble.
尽管他取得了成功，他仍然谦虚和谦逊。
B2 adjective /ˌʌnrɪˈzɒlvd/

unresolved

未解决的
Meaning
not solved or settled; remaining undecided or unclear
Example
The dispute remains unresolved despite several meetings.
尽管开了几次会议，这个争议仍未解决。
B2 adjective /ʌnˈwɜːrði/

Unworthy

不配; 没有价值
Meaning
not deserving respect or attention; lacking worth or merit
Example
He felt unworthy of such praise and recognition.
他觉得自己不配得到这样的赞扬和认可。
C1 adjective /ˌʌnəˈfɛktɪd/

unaffected

不受影响的, 自然的
Meaning
Not influenced or touched by something; genuine and natural.
Example
He remained unaffected by the criticism and kept working hard.
他对批评毫不受影响，继续努力工作。
B1 verb /ʌnˈlɒk/

unlock

解锁
Meaning
to open something that is locked; to make something accessible or available
Example
She used the key to unlock the door.
她用钥匙解锁了门。
B1 adjective /ʌnˈʃʊr/

unsure

不确定的
Meaning
not certain or confident; feeling doubt
Example
She felt unsure about the decision.
她对这个决定感到不确定。
B2 adjective /ʌnˈsuːtəbl/

Unsuitable

不适合; 不合适
Meaning
not fitting or appropriate for a particular purpose or situation
Example
This formal dress is unsuitable for a casual beach party.
这件正式的衣服不适合参加随意的海滩派对。
C2 adjective /ˌʌnəˈsweɪdʒd/

unassuaged

未缓解
Meaning
Not made less intense or relieved; unrelieved.
Example
His grief remained unassuaged despite the passage of time.
他的痛苦尽管时间流逝依然未缓解。
B2 adjective /ʌnˈraɪp/

Unripe

未成熟的
Meaning
not fully developed or matured; not ready to be eaten
Example
The unripe bananas will turn yellow in a few days.
未成熟的香蕉几天后会变黄。
B2 adjective /ʌnprəˈdʌk.tɪv/

Unproductive

无效的; 不起作用的
Meaning
not achieving much; not producing good results
Example
The meeting was unproductive and wasted everyone's time.
会议是无效的，浪费了大家的时间。
B2 adjective /ˌʌnrɪˈlaɪəbl/

Unreliable

不可靠的; 不能被信任或依赖
Meaning
not dependable; not able to be trusted or relied upon
Example
The old car is unreliable and breaks down frequently.
这辆老车不可靠，常常坏掉。
B2 adverb /ʌnˈplɛzəntli/

unpleasantly

令人不快地
Meaning
in a way that causes discomfort, annoyance, or displeasure; in an unfriendly or disagreeable manner
Example
The room was unpleasantly hot during the afternoon.
下午房间里热得令人不快。
C1 adjective /ˌjuːtɪlɪˈtɛəriən/

utilitarian

Meaning
Designed to be useful or practical rather than attractive; relating to the doctrine that actions are right if they are useful or for the benefit of a majority.
Example
The building had a simple utilitarian design.
C1 adjective /ˌʌnˈpɑr.də.nə.bəl/

Unpardonable

不可宽恕的
Meaning
too bad to be forgiven; inexcusable
Example
His betrayal of trust was an unpardonable offense.
他的背叛是不可原谅的罪行。
B2 adjective /ˌʌnkənˈtroʊld/

uncontrolled

无法控制的
Meaning
not restrained or managed; lacking control
Example
The wildfire spread in an uncontrolled manner, causing widespread damage.
野火以无法控制的方式蔓延，造成广泛破坏。
A1 adverb /ʌp/

up

向上
Meaning
towards a higher position or level
Example
He climbed up the ladder quickly.
他迅速爬上了梯子。
B1 adjective /ʌnˈjuzd/

Unused

未使用的; 没有被使用
Meaning
not being used; not having been used before
Example
There are many unused rooms in this old mansion.
这个古老的豪宅里有许多未使用的房间。
C2 adjective /ʌnˈtɛmpərd/

untempered

失控的
Meaning
not moderated or softened; lacking proper balance or control
Example
The untempered anger of the crowd caused chaos.
人群的失控愤怒引发了混乱。
C1 adjective /ˌʌnfɔːrˈsiːn/

unforeseen

Meaning
Not anticipated or predicted; unexpected.
Example
The project faced unforeseen challenges that delayed its completion.
B1 adjective /ʌnɪmˈplɔɪd/

Unemployed

失业
Meaning
without a job; not having paid work
Example
He has been unemployed for six months now.
他已经失业六个月了。
C1 noun /ˈʌndərˌstʌdi/

understudy

替身演员
Meaning
An actor who learns another's role to act as a replacement if needed.
Example
The understudy performed when the lead actor fell ill.
当主角生病时，替身演员上场表演。
C2 noun /ˈʌn.dɚˌstɔː.ri/

understory

下层植被
Meaning
The layer of vegetation beneath the main canopy of a forest.
Example
The understory of a rainforest is home to small mammals and insects.
雨林的下层植被是小型哺乳动物和昆虫的家园。
B2 adjective /ʌnprɪˈpɛrd/

Unprepared

未准备好
Meaning
not ready or able to deal with something
Example
He was unprepared for the difficult exam.
他对困难的考试毫无准备。