Union
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B1 noun /ˈjuːnjən/

Union

联合
Meaning
the action of joining or combining; a political unit formed from separate states
Example
The union of the two companies created a powerful corporation.
两家公司的联合创造了一个强大的公司。
C1 adjective /ˌʌnəˈdɔːrnd/

unadorned

简单的，未装饰的
Meaning
Plain and simple; not decorated.
Example
The room was unadorned, with only a table and a chair.
房间简单，只有一张桌子和一把椅子。
C2 verb /ʌnˈɑːrm/

unarm

解除武装
Meaning
to remove weapons from someone or to deprive of means of attack or defense
Example
The soldiers were ordered to unarm the prisoners.
士兵接到命令解除囚犯的武装。
C1 noun /ʌpˈhiːvəl/

upheaval

动荡
Meaning
a violent or sudden change or disruption to something
Example
The company faced a major upheaval after the sudden resignation of its CEO.
公司在其CEO突然辞职后经历了巨大的动荡。
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。
B2 adverb /ˈʌt.ə.li/

Utterly

完全地; 绝对地; 完整地
Meaning
completely; absolutely; totally
Example
The movie was utterly boring and I fell asleep.
电影完全无聊，我睡着了。
C2 verb /ˈʌndərˌraɪt/

underwrite

Meaning
To guarantee financial support, especially by agreeing to cover losses or risks; in insurance, to assess and accept risks.
Example
The bank agreed to underwrite the company's new bond issue.
B2 adjective /ʌnˈfeɪθ.fəl/

Unfaithful

不忠诚
Meaning
not loyal or true to a spouse, partner, or commitment
Example
He was unfaithful to his wife for many years.
他对妻子不忠诚多年。
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。
C1 verb /ʌpˈruːt/

uproot

拔除
Meaning
To pull something out of the ground; to remove or displace completely.
Example
They uprooted the old tree from the garden.
他们从花园里把老树拔了出来。
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。
B1 adjective /ˈʌpˌkʌmɪŋ/

upcoming

即将到来
Meaning
about to happen or appear
Example
The upcoming event will be held next week.
即将到来的活动将在下周举行。
C1 adjective /ʌnˈmænɪdʒəbəl/

Unmanageable

无法控制的; 失控
Meaning
difficult or impossible to control or handle
Example
The large class became unmanageable without proper supervision.
没有适当的监督，班级变得无法控制。
C2 adjective /ˈʌndjʊləs/

undulous

波浪形的
Meaning
Having a wavy surface or form.
Example
The artist painted the undulous sea at sunset.
艺术家在日落时画了波浪形的海洋。
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。
B2 adjective /ˈjuː.nɪ.faɪd/

unified

统一
Meaning
Made into a whole or joined together.
Example
A unified approach fosters better outcomes.
统一的方法促进了更好的结果。
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。
B2 adverb /ʌnˈfɛərli/

unfairly

不公平地
Meaning
In a manner that is not just, reasonable, or impartial
Example
He was treated unfairly by the committee.
他被委员会不公平地对待。
B2 adjective /ʌnˈiːkwəl/

Unequal

不平等; 不公正;
Meaning
not the same in quantity, size, or value; not fair or just
Example
The distribution of wealth is unequal in many countries.
财富的分配在许多国家是不平等的。
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。
A2 verb /ʌpˈset/

upset

烦扰
Meaning
to make someone worried, sad, or angry; to disturb
Example
The bad news upset everyone.
坏消息 upset 每个人。
B2 adjective /ʌnˈriːdəbl/

unreadable

难以辨认的
Meaning
not able to be read or understood clearly; illegible
Example
The doctor’s handwriting was completely unreadable.
医生的字迹完全难以辨认。
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。
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。
B2 noun /ˌʌndəˈɡrædʒuət/

undergraduate

本科生
Meaning
a student who has not yet earned a bachelor's degree
Example
She is an undergraduate studying computer science.
她是一个学习计算机科学的本科生。
B1 adjective /ʌnˈfeər/

Unfair

不公平; 不正当;
Meaning
not right or just; treating people in a way that favors some over others
Example
It's unfair to blame her for something she didn't do.
指责她做了她没有做的事是不公平的。
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 /ʌnˈpɒpjʊlə/

unpopular

不受欢迎的
Meaning
not liked or supported by many people
Example
The decision was unpopular with the public.
这个决定在公众中不受欢迎。
C1 adjective /ʌnˈvaɪəbl/

unviable

不可行的
Meaning
Not capable of working successfully; not feasible or practical.
Example
The project was deemed unviable due to high costs.
由于高昂的成本，该项目被认为不可行。
B2 verb /ˌʌndərˈteɪk/

undertake

承担
Meaning
to commit to and begin a task or project; to take on responsibility
Example
She decided to undertake a challenging project.
她决定承担一个具有挑战性的项目。
C2 adjective /ˌʌn.rɪˈdʒɛn.ər.ət/

unregenerate

顽固
Meaning
Not reformed or showing no signs of change; stubbornly refusing to reform or repent.
Example
He remained an unregenerate opponent of progress.
他仍然是进步的顽固反对者。
B2 noun /ʌnˈkɒnʃəsnəs/

unconsciousness

无意识
Meaning
the state of being unaware of and unable to respond to one's surroundings
Example
After the accident, he was in a state of unconsciousness for several hours.
事故后，他昏迷了几个小时。
B2 adjective /ˌʌndɪˈstɜːrbd/

Undisturbed

未打扰
Meaning
not interrupted or interfered with; calm and peaceful
Example
She slept undisturbed for eight hours.
她睡了八个小时没有打扰。
B1 adjective /ˌʌnɪkˈspektɪd/

Unexpected

出乎意料的; 令人惊讶的
Meaning
not expected or anticipated; surprising
Example
The unexpected news left everyone speechless.
出乎意料的消息让所有人都哑口无言。
C1 adjective /juːˈbɪkwɪtəs/

ubiquitous

无处不在
Meaning
Existing or being everywhere at the same time.
Example
Social media has become ubiquitous among young people.
社交媒体在年轻人中变得无处不在。
B2 adjective /ʌnˈprɒf.ɪ.tə.bl̩/

Unprofitable

无利可图
Meaning
not yielding profit or gain; not producing financial benefit
Example
The unprofitable business was forced to close down after three years.
这个无利可图的生意在三年后被迫关闭。
C2 noun/verb /ˈʌpˌkæst/

upcast

向上投掷
Meaning
Verb: To cast or throw upward. Noun: Something thrown or directed upward.
Example
The fisherman upcast his net into the air.
渔夫把他的网投向空中。
C1 noun /ʌnɪmˈpɔːrtəns/

unimportance

不重要
Meaning
the state or quality of being insignificant or not important
Example
He dismissed the issue with a sense of unimportance.
他以無關緊要的態度忽略了這個問題。
B2 adjective /ʌnprəˈfɛʃ.ən.əl/

Unprofessional

不专业
Meaning
not conforming to the standards expected in a particular profession
Example
His unprofessional behavior led to his dismissal from the company.
他的不专业行为导致他被公司解雇。
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。
C2 adjective /ʌnˈælɔɪd/

unalloyed

纯净
Meaning
Pure, complete, and not mixed with anything else.
Example
She felt unalloyed joy at the news of her success.
她听到成功的消息时感到纯粹的喜悦。
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 noun /ˌjuːzɜːrˈpeɪʃən/

usurpation

篡夺
Meaning
The act of taking someone's power or property illegally or by force.
Example
The general's usurpation of the presidency led to political unrest.
将军对总统职位的篡夺导致了政治动荡。
A1 verb /juːz/

use

使用
Meaning
to employ something for a purpose; to take advantage of
Example
I use my computer for work and entertainment.
我用我的计算机来工作和娱乐。
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。
B2 adjective ʌnˈprɛsɪˌdɛntɪd

unprecedented

前所未有
Meaning
Never done or known before; without previous example.
Example
Unprecedented advancements in science changed human lives.
科学上的前所未有的进展改变了人类的生活。
C2 verb /ˌʌndərˈɡɜːrd/

undergird

支持，强化
Meaning
to provide support or foundation for; to strengthen
Example
Strong values undergird a healthy society.
强大的价值观支撑着一个健康的社会。
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。
C1 adjective /ʌnˈkæni/

uncanny

不可思议
Meaning
Strange or mysterious, especially in an unsettling way.
Example
She has an uncanny ability to predict the future.
她有一种不可思议的能力来预测未来。
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。
C1 adjective /ʌnˈkwaɪ.ət/

Unquiet

不安的; 焦虑的; 激动的
Meaning
restless; unable to remain still or quiet; anxious or troubled
Example
She spent an unquiet night worrying about the exam results.
她度过了一个不安的夜晚，担心考试结果。
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。
B1 adjective /ʌnˈwel/

Unwell

不舒服; 生病
Meaning
not in good health; feeling sick or ill
Example
She has been feeling unwell since yesterday.
她从昨天开始感到不舒服。
B2 adverb /ʌnˈkɒnʃəsli/

unconsciously

无意识地
Meaning
without being aware of one's actions or surroundings
Example
She unconsciously tapped her foot to the rhythm of the music.
她无意识地跟着音乐的节奏轻轻跺脚。
C2 noun /ˈjuːnɪvəˌlɛns/

univalence

单价性
Meaning
The state of having a single valence or combining power, especially in chemistry.
Example
Hydrogen is characterized by its univalence in chemical reactions.
氢气在化学反应中以其单价性为特点。
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.
B2 adjective /ʌnˈberəbəl/

Unbearable

无法忍受
Meaning
too painful, annoying, or unpleasant to tolerate; impossible to endure
Example
The heat in the desert was unbearable.
沙漠中的热度是无法忍受的。
C1 adjective /ʌnˈruːli/

Unruly

不守规矩的; 乱七八糟的;
Meaning
difficult to control or manage; disorderly and disruptive
Example
The unruly crowd refused to follow the safety instructions.
那群无法控制的人群拒绝遵循安全指令。
B1 preposition, adverb, adjective /ˌʌndərˈniːθ/

underneath

在……下面
Meaning
Located directly below or beneath something
Example
The keys were hidden underneath the pile of papers.
钥匙被隐藏在那堆文件下面。
B2 adjective /ˌʌnˈkɔːrdɪneɪtɪd/

uncoordinated

不协调; 笨拙
Meaning
lacking coordination, not well-organized or clumsy in movement
Example
His movements were uncoordinated, making him prone to accidents.
他的动作不协调，使他容易发生意外。
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。
C2 verb /ʌpˈbreɪd/

upbraid

斥责
Meaning
To scold or criticize someone harshly.
Example
The teacher upbraided the student for being late again.
老师因为学生再次迟到而训斥了他。
C2 noun /juːˌtɪlɪˈtɛəriənɪzəm/

utilitarianism

功利主义
Meaning
The ethical theory that actions are right if they are useful or for the benefit of the majority.
Example
Utilitarianism suggests that we should act to maximize overall happiness.
功利主义认为我们应该采取行动，以最大化整体幸福。
B1 adjective /ʌnˈfrɛndli/

unfriendly

不友好的
Meaning
not kind or welcoming; hostile or cold in behavior or attitude
Example
The shop owner seemed unfriendly to new customers.
店主对新顾客显得不友好。
B2 adjective /ʌnˈnætʃərəl/

Unnatural

不自然的
Meaning
not existing in nature; artificial; forced
Example
The actor's smile looked unnatural and forced.
演员的笑容看起来很不自然，很勉强。
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 noun /ˌjuːnɪˈfɔːrməti/

Uniformity

一致性；统一性；相同状态
Meaning
the quality of being uniform; consistency or sameness
Example
The uniformity of the design created a pleasing visual effect.
设计的一致性创造了一个吸引人的视觉效果。
C2 adjective /ˌʌltrəˈmɒnteɪn/

ultramontane

教皇支持者
Meaning
beyond the mountains, especially referring to support for the Pope over local church authority
Example
The debate highlighted the ultramontane position in church politics.
辩论突出了教会政治中超山的立场。
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 /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。
B1 noun /juːˈten.səlz/

Utensils

餐具
Meaning
tools or implements used for cooking, eating, or serving food
Example
Please wash all the cooking utensils after preparing dinner.
请在准备晚餐后清洗所有的厨房用具。
C1 adjective /ˌʌnɪnˈhɪbɪtɪd/

uninhibited

不受抑制的
Meaning
Not restrained or restricted; free in behavior or expression.
Example
She gave an uninhibited laugh at the joke.
她在笑话中放声大笑。
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 /ˌʌndərˈsaɪzd/

undersized

尺寸过小
Meaning
Smaller than the usual or expected size.
Example
The undersized puppy struggled to keep up with its siblings.
这只尺寸过小的小狗很难跟上它的兄弟姐妹。
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。
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。
C1 adjective /ˌʌnprɪˈtɛnʃəs/

unpretentious

谦虚的
Meaning
modest; not attempting to impress others with appearance or importance
Example
She lives in an unpretentious home but is very happy.
她住在一个谦虚的家里，但非常快乐。
C1 noun /ˈʌp.tɜːn/

upturn

改善
Meaning
An improvement or upward trend in a situation, especially in business or economy.
Example
The company experienced an upturn in sales last quarter.
该公司在上个季度销售情况有所改善。
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 /ˈʌpərˌmoʊst/

uppermost

最高
Meaning
situated at the highest place or most important
Example
Her family's safety was uppermost in her mind during the crisis.
她在危机期间心里最重要的是家庭的安全。
C1 adjective /ʌnˈsoʊld/

unsold

未售出的
Meaning
not sold; remaining without a buyer
Example
The unsold goods were returned to the warehouse.
未售出的商品被退回仓库。
C2 adjective /juːˈʒʊəriəs/

usurious

高利贷的
Meaning
Charging excessively high interest rates on loans.
Example
The bank was accused of offering loans at usurious rates.
该银行被指控以高利贷利率提供贷款。
C1 adjective /ˌʌnˈɪntɪmeɪtɪŋ/

unintimating

没有暗示
Meaning
Not giving a hint or suggestion; not indicating.
Example
His unintimating tone gave no clue of his true feelings.
他的没有暗示的语气没有透露他真正的感受。
B2 noun /ˈɜː.dʒən.si/

Urgency

紧急
Meaning
the quality of requiring immediate action or attention; pressing importance
Example
The urgency of the situation required immediate medical attention.
情况的紧急性要求立即的医疗关注。
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。
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 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。
C1 noun /ˈʌndərˌwɜːrld/

underworld

地下世界
Meaning
The criminal world of organized crime or the mythical world of the dead.
Example
The detective spent years studying the secrets of the underworld.
侦探花了很多年研究地下世界的秘密。
C2 adjective /juːˈbɪkwɪtəs/

ubiquitious

无处不在
Meaning
Present, appearing, or found everywhere.
Example
Smartphones have become ubiquitous in modern society.
智能手机已经在现代社会中无处不在。
C2 verb /ʌnˈkaʊtʃ/

uncouch

从沙发上移开（罕见用法）
Meaning
to remove from a couch or to release from being laid down (rare/archaic usage)
Example
The surgeon attempted to uncouch the cataract.
外科医生试图去除白内障。
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 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。
B1 adjective /ʌnˈjuː.ʒu.əl/

Unusual

不寻常; 奇怪;
Meaning
not typical; strange; different from what is normal
Example
She wore an unusual dress to the party.
她穿了一件不寻常的衣服去参加派对。
C2 adjective /ʌnˈwiːldi/

unwieldy

笨重
Meaning
Difficult to carry or move because of its size, shape, or weight.
Example
The box was too unwieldy to carry up the stairs.
这个盒子太笨重了，无法把它提上楼梯。
C1 noun /ˈʌndərˌteɪkər/

undertaker

殡葬员
Meaning
A person whose job is to prepare the dead for burial and arrange funerals.
Example
The undertaker prepared the body for the funeral service.
殡葬员为葬礼服务准备了尸体。
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。
C1 adjective /ʌnˈtʃælɪndʒd/

Unchallenged

无可争议的; 被接受的没有反对; 没有对手
Meaning
not disputed or questioned; accepted without opposition; having no rival
Example
He remained the unchallenged champion for five years.
他五年保持不败的冠军。
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。
C1 adjective /ˌʌnfɔːrθˈkʌmɪŋ/

unforthcoming

不合作的
Meaning
Not willing to talk or provide information; uncooperative.
Example
The witness was unforthcoming about what he had seen.
证人对于他所见的情况不合作。
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 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。
C2 adjective /ˌʌnɪmˈpiːtʃəbl/

unimpeachable

无可指摘
Meaning
Not able to be doubted, questioned, or criticized; completely trustworthy.
Example
She is known for her unimpeachable honesty.
她因其无可指摘的诚实而闻名。
B1 adjective /ʌnˈfɔːr.tʃən.ət/

Unfortunate

不幸的；遗憾的
Meaning
having bad luck; regrettable or unlucky
Example
It was unfortunate that the meeting was cancelled at the last minute.
很不幸的是，会议在最后一刻被取消了。
B1 noun /ˈjuːs.fəl.nəs/

Usefulness

有用性
Meaning
the quality of being useful; practical value or helpfulness
Example
The usefulness of this tool became apparent during the project.
这个工具的有用性在项目过程中变得显而易见。
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。
C2 adjective /ʌnˈlɛtəd/

unlettered

文盲
Meaning
lacking education or the ability to read and write; illiterate
Example
The unlettered villagers relied on oral traditions to preserve their history.
那些文盲村民依赖口头传统来保存他们的历史。
B2 adjective /ʌnˈhɛlpfəl/

unhelpful

没有帮助的
Meaning
not providing help or support; making a situation harder rather than easier
Example
His unhelpful attitude slowed down the entire project.
他没有帮助的态度拖慢了整个项目。
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。
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。
C1 adjective /ʌnˈseɪvəri/

unsavory

令人不快
Meaning
Disagreeable, unpleasant, or morally offensive.
Example
The politician was linked to an unsavory scandal.
那位政治家与一宗令人不快的丑闻有关。
C1 adjective /ʌnˈbraɪdld/

unbridled

无法控制的
Meaning
Uncontrolled and unrestrained.
Example
The protesters showed unbridled enthusiasm for change.
抗议者展示了对改变的无法抑制的热情。
B1 adjective /ʌnˈlaɪkli/

Unlikely

不太可能; 不大可能
Meaning
not likely to happen; improbable
Example
It's unlikely to rain today with such clear skies.
今天晴空万里，几乎不可能下雨。
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。
B2 verb /ˌʌndərˈmaɪn/

undermine

削弱
Meaning
to gradually weaken or damage something or someone
Example
Constant criticism can undermine a child's confidence.
持续的批评可能会削弱孩子的自信心。
C1 adjective /ʌlˈtɪəriər/

ulterior

隐藏的动机
Meaning
hidden or secret, often with a selfish motive
Example
He invited her with an ulterior motive.
他带着隐藏的动机邀请了她。
C1 noun /ˌʌnprɪˈdɪktəˌbɪləti/

unpredictability

不可预测性
Meaning
The quality of being impossible to predict or anticipate.
Example
The unpredictability of the weather made the trip uncertain.
天气的不可预测性使得旅行充满不确定性。
B1 adjective /ʌnˈsɜːrtən/

Uncertain

不确定
Meaning
not able to be relied on; not known or definite; not having reliable knowledge
Example
I am uncertain about my future career plans.
我对未来的职业规划感到不确定。
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。
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 /ʌnˈlɔːfl/

Unlawful

非法; 不合法
Meaning
not authorized by law; illegal
Example
The court declared the search unlawful.
法院宣布搜索是非法的。
C1 adjective /ʌnˈsaɪtli/

unsightly

难看
Meaning
Unpleasant to look at; ugly.
Example
The garbage pile created an unsightly view in the park.
垃圾堆在公园里创造了一个难看的景象。