unaffected
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C1 adjective /ˌʌnəˈfɛktɪd/

unaffected

無影響な, 自然な
Meaning
Not influenced or touched by something; genuine and natural.
Example
He remained unaffected by the criticism and kept working hard.
彼は批判に動じることなく、懸命に働き続けました。
C1 adjective /ˌʌnəbˈtruːsɪv/

unobtrusive

目立たない
Meaning
not attracting attention; blending in without causing notice
Example
The security cameras are designed to be unobtrusive.
セキュリティカメラは目立たないように設計されています。
C2 noun /ˈjuːʒəri/

usury

高利貸し
Meaning
The practice of lending money at unreasonably high interest rates.
Example
The law strictly prohibits usury.
法律は高利貸しを厳しく禁止しています。
A2 adjective /ʌnˈkʌmfətəbl/

Uncomfortable

不快
Meaning
causing or feeling physical or emotional discomfort
Example
He felt uncomfortable during the long meeting.
長い会議の間、彼は不快に感じました。
C2 noun /ˈjuːzjuːfrʌkt/

usufruct

使用権
Meaning
The legal right to use and enjoy the benefits of someone else’s property without owning it.
Example
The tenant had the usufruct of the land but not its ownership.
借家人は土地の使用権を持っていたが、所有権はなかった。
C2 adjective /ʌnˈfeɪnd/

unfeigned

本物
Meaning
genuine; not pretended or insincere
Example
She expressed unfeigned joy at her friend's success.
彼女は友達の成功に対して本物の喜びを表現しました。
B2 adjective /ʌnˈriːzənəbəl/

unreasonable

理不尽な
Meaning
not guided by reason or fairness; excessive or extreme beyond what is acceptable
Example
The manager made an unreasonable demand that no one could realistically meet.
マネージャーは理不尽な要求をした。
C2 adjective /ˌʌnsɛrəˈmoʊniəs/

unceremonious

儀式なし/無礼
Meaning
Done without formality or courtesy; abrupt or rude.
Example
He made an unceremonious exit from the party.
彼はパーティーから儀式なしで退出しました。
C2 adjective /ʌkˈsɔːriəs/

uxorious

妻に対して過度に愛情深い
Meaning
excessively fond of or submissive to one's wife
Example
He was so uxorious that he agreed with everything his wife said.
彼は妻に対してそれほどまでに uxorious で、妻が言ったことすべてに同意しました。
B2 adverb /ʌnˈnesəserəli/

Unnecessarily

不必要に
Meaning
to a greater extent than is needed; without necessity
Example
Don't worry unnecessarily about the exam.
試験について不必要に心配しないでください。
B1 adjective /ʌnˈklɪər/

unclear

不明確
Meaning
not easy to understand; vague or ambiguous
Example
The instructions were unclear, so I asked for clarification.
指示が不明確だったので、私は説明を求めました。
B2 adjective /ˌʌnˈkɔːrdɪneɪtɪd/

uncoordinated

不器用; 協調性のない
Meaning
lacking coordination, not well-organized or clumsy in movement
Example
His movements were uncoordinated, making him prone to accidents.
彼の動きは不器用で、事故を起こしやすかった。
B2 adjective /ʌnprɪˈpɛrd/

Unprepared

準備不足
Meaning
not ready or able to deal with something
Example
He was unprepared for the difficult exam.
彼は難しい試験に準備していなかった。
B2 adjective /juːˈnæn.ɪ.məs/

Unanimous

全会一致
Meaning
fully in agreement; shared by all
Example
The committee reached a unanimous decision.
委員会は全会一致の決定を下しました。
C2 adjective /ʌnˈʌtərəbl/

unutterable

言葉では表現できない
Meaning
Too great, intense, or awful to be expressed or described in words.
Example
She was filled with unutterable joy at the news of her success.
彼女は成功の知らせを聞いたとき、言葉では言い表せないほどの喜びで満たされていました。
C1 adjective /ʌnˈtaɪmli/

Untimely

不適切なタイミングで
Meaning
happening at an inappropriate or inconvenient time; premature
Example
His untimely death at the age of thirty shocked everyone.
彼の不適切なタイミングでの死は30歳でみんなを驚かせた。
B1 noun /juːˈten.səlz/

Utensils

食器
Meaning
tools or implements used for cooking, eating, or serving food
Example
Please wash all the cooking utensils after preparing dinner.
ディナーを準備した後、すべての料理用具を洗ってください。
C2 adjective /ʌnˈɡeɪnli/

ungainly

不器用
Meaning
Awkward, clumsy, or lacking grace in movement or appearance.
Example
The tall boy moved in an ungainly manner.
背の高い男の子は不器用な仕草で動いた。
B2 adjective /ʌnˈskɪld/

Unskilled

未熟な; 技術のない労働者
Meaning
lacking technical training or ability; not requiring special skills
Example
Many unskilled workers are looking for training opportunities.
多くの未熟な労働者がトレーニングの機会を探しています。
B1 adjective /ˌʌnsəkˈsesfl/

Unsuccessful

失敗した; 成功しなかった;
Meaning
not achieving desired aims or results; failing to accomplish a purpose
Example
His unsuccessful attempt to climb the mountain left him disappointed.
彼の失敗した山登りの試みは彼を失望させた。
C1 noun /ˌʌl.tɪˈmeɪ.təm/

Ultimatum

最終通告
Meaning
a final demand or statement of terms, the rejection of which will result in retaliation
Example
The boss gave him an ultimatum: improve or be fired.
上司は彼に最終通告を与えた：改善するか、解雇されるかだ。
A2 noun /ˌʌpˈsteəz/

Upstairs

上の階
Meaning
on or to an upper floor of a building; the upper floor or floors
Example
She went upstairs to her bedroom to rest.
彼女は休憩するために自分の寝室に上がった。
C1 adjective /ʌnˈvɔɪst/

unvoiced

未表現
Meaning
not expressed in speech; in phonetics, a sound produced without vocal cord vibration
Example
The student kept her opinion unvoiced during the meeting.
学生は会議中に自分の意見を未表現のままにしておいた。
B2 adjective /ʌnˈtʃeɪndʒɪŋ/

unchanging

変わらない
Meaning
remaining the same over time; not changing
Example
Her love for her family was unchanging throughout the years.
彼女の家族への愛は何年にもわたって変わらなかった。
B1 adjective /ˈɜːrdʒənt/

Urgent

緊急
Meaning
requiring immediate action or attention; pressing
Example
The patient needs urgent medical attention.
患者は緊急の医療支援が必要です。
B2 adjective /ˌʌnrɪˈlaɪəbl/

Unreliable

信頼できない; 信頼や依存ができない
Meaning
not dependable; not able to be trusted or relied upon
Example
The old car is unreliable and breaks down frequently.
その古い車は信頼できず、よく壊れます。
B2 adjective /ʌnˈθɪŋkəbl/

Unthinkable

想像を絶する
Meaning
impossible to conceive or imagine; beyond belief or consideration
Example
It was unthinkable that such a tragedy could happen in our peaceful town.
私たちの平和な街でそのような悲劇が起こるなんて、想像を絶していました。
C2 adjective /ʌnˈflɛdʒd/

unfledged

未熟な
Meaning
Inexperienced, immature, or not fully developed.
Example
The unfledged writer struggled to complete his first novel.
未熟な作家は、最初の小説を完成させるのに苦労しました。
C2 adjective /ʌpˈrɔːr.i.əs/

uproarious

非常に面白い
Meaning
Extremely funny or noisy; causing loud laughter or commotion.
Example
The comedian's jokes were absolutely uproarious.
コメディアンのジョークは絶対に非常に面白かったです。
B2 adjective /ʌnˈwaɪz/

unwise

賢明でない
Meaning
Showing poor judgment; not sensible or prudent.
Example
It would be unwise to invest all your money in one company.
すべてのお金を1つの会社に投資するのは賢明でないことです。
C2 noun /ˈʌndərlɪŋ/

underling

部下
Meaning
a person of low rank or importance; a subordinate
Example
The manager ordered his underlings to finish the task quickly.
マネージャーは部下に仕事を迅速に終わらせるよう命じました。
C1 adjective /ʌnˈkuːθ/

uncouth

無作法
Meaning
Lacking good manners, refinement, or grace; awkward or rough.
Example
His uncouth behavior shocked the guests at the party.
彼の無作法な行動はパーティーのゲストを驚かせました。
C1 noun /juːnəˈnɪməti/

Unanimity

全会一致
Meaning
complete agreement among all members of a group
Example
The committee reached unanimity on the new policy.
委員会は新しい方針について全会一致に達しました。
C2 adjective /ʌnˈkɒnʃənəbl/

unconscionable

不正当な
Meaning
shockingly unfair or unreasonable
Example
The company made unconscionable profits from the crisis.
その会社は危機から不正当な利益を得ました。
B2 adjective /ʌnˈkɒmən/

uncommon

珍しい
Meaning
rare, unusual, or remarkable
Example
It is uncommon to see snow in this region.
この地域で雪を見るのは珍しい。
B2 adverb /ˈʌt.ə.li/

Utterly

完全に; 絶対に; 完全に
Meaning
completely; absolutely; totally
Example
The movie was utterly boring and I fell asleep.
その映画は完全に退屈で、私は寝てしまいました。
B2 adjective /ʌnfəˈmɪl.jər/

Unfamiliar

不明な; 見知らぬ
Meaning
not known or recognized; strange
Example
The city was unfamiliar to me since I had never been there before.
その都市は私にとって見知らぬ場所でした。なぜなら、私はそこに行ったことがなかったからです。
B1 adjective /ʌnˈwel/

Unwell

体調不良; 病気
Meaning
not in good health; feeling sick or ill
Example
She has been feeling unwell since yesterday.
彼女は昨日から体調が悪い。
C1 verb /ˌʌndərˈsteɪt/

understate

過小評価する
Meaning
To describe something as being less important or serious than it really is.
Example
He tends to understate his achievements.
彼は自分の業績を過小評価する傾向があります。
B2 adjective /ʌnˈiːkwəl/

Unequal

不平等; 不正;
Meaning
not the same in quantity, size, or value; not fair or just
Example
The distribution of wealth is unequal in many countries.
多くの国々では、富の分配は不平等です。
C1 adjective /ʌnˈfɔːltərɪŋ/

unfaltering

不屈不挠
Meaning
Steady and resolute; not weakening or hesitating
Example
She continued with unfaltering determination.
彼女は不屈不挠の決意で続けた。
C1 adjective /ˌʌnprɪˈtɛnʃəs/

unpretentious

控えめな
Meaning
modest; not attempting to impress others with appearance or importance
Example
She lives in an unpretentious home but is very happy.
彼女は控えめな家に住んでいますが、とても幸せです。
C1 noun ˌʌndərˈprɪvəlɪdʒd ɡruːps

underprivileged groups

恵まれないグループ
Meaning
Groups of people who lack basic necessities or advantages that are available to other members of society.
Example
Underprivileged groups benefit from social initiatives.
恵まれないグループは社会的なイニシアティブから利益を得ます。
C1 adjective /ˈʌndərhænd/

underhand

不正
Meaning
done secretly and dishonestly; deceitful
Example
The politician was accused of using underhand tactics to win the election.
その政治家は選挙に勝つために不正な手段を使ったとして非難されました。
A1 adverb /ʌp/

up

上
Meaning
towards a higher position or level
Example
He climbed up the ladder quickly.
彼はすばやくはしごを上った。
B2 adjective /ˈʌpˌraɪt/

Upright

正直で道徳的に正しい; 垂直または立っている位置
Meaning
honest and morally correct; vertical or erect in position
Example
She is known for being an upright and honest businesswoman.
彼女は正直で正しいビジネスウーマンとして知られています。
B2 noun /ʌnəˈbɪləti/

unability

無能力
Meaning
the state of being unable to do something; incapacity
Example
His unability to solve the problem caused delays in the project.
彼の問題を解決する無能力はプロジェクトの遅延を引き起こした。
C2 noun /ˌjuːnɪˈtɛəriən/

unitarian

ユニタリアン
Meaning
A person who believes that God exists as one entity rather than as a Trinity; a member of a religious denomination that emphasizes individual freedom of belief.
Example
The Unitarian church is known for its inclusive and open-minded approach.
ユニタリアン教会は、その包括的で開かれた考え方で知られています。
C1 adjective /ʌnˈmɒdɪfaɪd/

unmodified

未変更の
Meaning
not changed from its original form or state
Example
The data was used in its unmodified form for analysis.
データは未変更の形で分析に使用された。
C1 adjective /ʌnˈsɪvəl/

Uncivil

無礼な; 不作法な;
Meaning
not polite or courteous; rude and discourteous in behavior
Example
His uncivil remarks during the meeting offended everyone present.
会議中の彼の無礼な発言は、出席者全員を不快にさせた。
C2 adjective /ˈʌndjʊleɪtɪŋ/

undulating

波打つ
Meaning
Having a smoothly rising and falling form or motion like waves.
Example
We drove through undulating hills.
私たちは起伏のある丘をドライブしました。
A1 preposition /ˈʌndər/

under

下
Meaning
in or to a lower position than something
Example
The cat is under the table.
猫はテーブルの下にいます。
C1 adjective /ʌnˈseɪvəri/

unsavory

不快
Meaning
Disagreeable, unpleasant, or morally offensive.
Example
The politician was linked to an unsavory scandal.
その政治家は不快なスキャンダルに関連していました。
B2 adjective /ʌnˈbæləns/

Unbalanced

不均衡な; 不安定な
Meaning
not balanced; lacking stability or equilibrium; mentally unstable
Example
The unbalanced table kept wobbling.
不均衡なテーブルは揺れ続けていた。
B1 adjective /ʌnˈwɒn.tɪd/

Unwanted

望まれない
Meaning
not desired or welcome; not wanted
Example
He felt like an unwanted guest at the meeting.
彼は会議で望まれない客のように感じた。
B1 adjective /ˌʌndərˈstændəbl/

understandable

理解できる
Meaning
Able to be understood; reasonable or justifiable.
Example
Her reaction was understandable given the situation.
その反応は状況を考慮すると理解できるものでした。
C2 adjective /ʌnˈtræməld/

untrammeled

制限のない自由
Meaning
Not restricted or hampered; free and unrestricted.
Example
She enjoyed untrammeled freedom in her new life abroad.
彼女は海外での新しい生活で制限のない自由を楽しんでいた。
B2 adjective /ʌnˈfeɪv(ə)rəbəl/

unfavorable

不利な
Meaning
not beneficial or advantageous; showing disapproval or opposition
Example
The proposal received an unfavorable response from the committee.
その提案は委員会から不利な反応を受けました。
C2 adjective /ˈʌndjʊləs/

undulous

波打つ
Meaning
Having a wavy surface or form.
Example
The artist painted the undulous sea at sunset.
アーティストは夕日に照らされた波打つ海を描きました。
B2 adjective /ʌnˈsteɪbəl/

Unstable

不安定
Meaning
likely to change; not steady or secure; unsteady
Example
The unstable economy made people worried about their jobs.
不安定な経済は、人々を自分たちの仕事について心配させました。
B2 verb /ʌnˈveɪl/

unveil

発表する
Meaning
to reveal or disclose something, especially in a formal manner
Example
The company will unveil a new product next week.
会社は来週新製品を発表します。
B1 adjective /ʌnˈkʊkt/

uncooked

生の
Meaning
Not cooked; in a raw state.
Example
Eating uncooked meat can be dangerous.
生肉を食べるのは危険です。
B2 adjective /ʌnˈfɪt/

Unfit

不適格; 不適当;
Meaning
not in good physical condition; unsuitable or inappropriate
Example
He was declared unfit for military service due to his poor health.
彼は健康状態が悪いため、軍務には不適格と宣告されました。
C2 noun /ˈʌmbrɪdʒ/

umbrage

怒り, 不満
Meaning
A feeling of resentment or offense.
Example
She took umbrage at his rude remark.
彼女は彼の無礼な発言に怒りを感じた。
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.
その討論は教会政治におけるウルトラモンタンの立場を浮き彫りにした。
B1 adjective /ʌnɪmˈplɔɪd/

Unemployed

失業中
Meaning
without a job; not having paid work
Example
He has been unemployed for six months now.
彼はすでに6ヶ月間失業しています。
B2 adverb /ʌnˈkɒnʃəsli/

unconsciously

無意識に
Meaning
without being aware of one's actions or surroundings
Example
She unconsciously tapped her foot to the rhythm of the music.
彼女は無意識に音楽のリズムに合わせて足をトントンしていた。
B2 adjective /ʌnˈsiːn/

Unseen

見えない; 前に見たり気づいたりしたことがない
Meaning
not previously seen or noticed; invisible; hidden
Example
The unseen forces of nature can be very powerful.
自然界の見えない力は非常に強力である可能性があります。
C1 adjective /ʌnˈsəʊʃəl/

unsocial

非社交的な
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.
彼は一人で働くために非社交的な時間を好む。
B2 noun /ʌnˈkɒnʃəsnəs/

unconsciousness

無意識
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.
事故の後、彼は数時間意識を失っていた。
C2 verb /ʌnˈkaʊtʃ/

uncouch

ソファから取り除く（稀な意味）
Meaning
to remove from a couch or to release from being laid down (rare/archaic usage)
Example
The surgeon attempted to uncouch the cataract.
外科医は白内障を取り除こうとしました。
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.
C2 verb /ˈʌndjʊleɪt/

undulate

波打つ
Meaning
To move with a smooth, wave-like motion.
Example
The snake undulated across the sand.
ヘビは砂の上をうねうねと進んでいった。
B2 adjective /ʌnˌkənˈfɜːmd/

Unconfirmed

未確認; 未検証;
Meaning
not confirmed as true or definite; not verified or substantiated
Example
The report remains unconfirmed until we receive official verification.
報告書は公式の確認が得られるまで未確認のままです。
B2 adjective /ˌʌnəˈveɪləbəl/

unavailable

利用できない
Meaning
Not able to be obtained, reached, or used; not present or accessible.
Example
The manager was unavailable to take calls during the meeting.
マネージャーは会議中に電話に出られませんでした。
B1 adjective /ˈʌpˌkʌmɪŋ/

upcoming

今後の
Meaning
about to happen or appear
Example
The upcoming event will be held next week.
今後のイベントは来週行われます。
B2 adjective /ʌnˈlɔːfl/

Unlawful

違法; 不法
Meaning
not authorized by law; illegal
Example
The court declared the search unlawful.
裁判所はその捜索を不法と宣言しました。
B2 adjective /ˌʌndərˈlaɪɪŋ/

underlying

根本的な
Meaning
basic or hidden but important; forming the foundation of something
Example
The underlying reason for the conflict was never addressed.
その対立の根本的な理由は決して対処されませんでした。
B2 adjective /ˌʌndɪˈzaɪərəbl/

Undesirable

望ましくない; 有害な; 不快な
Meaning
not wanted or wished for; harmful or unpleasant
Example
The new policy had several undesirable consequences.
新しい政策は幾つか望ましくない結果を招いた。
C2 adjective /ʌnˈsʌlid/

unsullied

汚れのない
Meaning
not spoiled or made impure; perfectly clean or pure
Example
His reputation remained unsullied despite the accusations.
彼の評判は告発にもかかわらず汚れのないままでした。
C2 noun/verb /ˈʌpˌkæst/

upcast

上に投げる
Meaning
Verb: To cast or throw upward. Noun: Something thrown or directed upward.
Example
The fisherman upcast his net into the air.
漁師は彼の網を空中に投げた。
B1 adjective /ʌnˈjuː.ʒu.əl/

Unusual

異常な; 奇妙な;
Meaning
not typical; strange; different from what is normal
Example
She wore an unusual dress to the party.
彼女はパーティーに異常なドレスを着ていた。
C1 noun ˈʌp.raɪ.zɪŋ

uprising

反乱
Meaning
An act of resistance or rebellion; a revolt against an authority or government.
Example
The uprising marked the beginning of the revolution.
反乱は革命の始まりを示しました。
A2 adjective /ʌnˈhæp.i/

Unhappy

不幸な; 悲しい
Meaning
not happy; feeling sad or displeased; unfortunate or undesirable
Example
He was unhappy with the results of his exam.
彼は試験の結果に不満でした。
C1 adjective /ʌnˈskeɪðd/

unscathed

無傷
Meaning
Without suffering any injury, damage, or harm.
Example
She escaped from the accident unscathed.
彼女は事故から無傷で逃げ出した。
C1 verb /ʌnˈnɜːrv/

unnerve

自信を失う
Meaning
to make someone lose confidence, courage, or composure
Example
The hostile questions began to unnerve the witness.
敵意のある質問が証人を動揺させ始めた。
B2 adjective /ʌnprəˈdʌk.tɪv/

Unproductive

非生産的; 効率が悪い
Meaning
not achieving much; not producing good results
Example
The meeting was unproductive and wasted everyone's time.
会議は非生産的で、全員の時間を無駄にしました。
C2 adjective /ˈɜːrsaɪn/

ursine

クマのような
Meaning
Relating to or resembling a bear.
Example
The man’s ursine strength amazed everyone.
その男のクマのような力は、みんなを驚かせました。
B2 verb /ˌʌndərˈɛstɪmeɪt/

underestimate

過小評価する
Meaning
To judge something as less important or smaller than it really is.
Example
Never underestimate the power of teamwork.
決してチームワークの力を過小評価しないでください。
C2 verb /ʌnˈjoʊk/

unyoke

束縛から解放する
Meaning
To release from a yoke or to free from restraint or obligation.
Example
The farmer unyoked the oxen after a long day of work.
農夫は長い労働の後に牛の首輪を外した。
C2 adjective /ʌnˈtʃeɪst/

Unchaste

不道徳な; 不潔な;
Meaning
not celibate; having engaged in sexual relations; lacking moral purity
Example
The conservative society considered her behavior unchaste and improper.
保守的な社会は彼女の行動を不道徳で不適切だと考えた。
C1 verb /ˌʌndəˈreɪt/

underrate

過小評価
Meaning
to fail to recognize the full value or importance of something or someone
Example
Many people underrate the benefits of regular exercise.
多くの人々が定期的な運動の利点を過小評価しています。
B2 adverb /ʌnˈsɜːrtənli/

uncertainly

不確かに
Meaning
in a way that shows doubt or lack of certainty
Example
She glanced uncertainly at the complicated instructions.
彼女は複雑な指示を不確かに見つめた。
B2 adjective /ˌʌnprɪˈdɪktəbəl/

unpredictable

予測できない
Meaning
not able to be predicted; changing suddenly and unexpectedly
Example
The weather in this region is highly unpredictable.
この地域の天気はとても予測できない。
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.
B1 adjective /ʌnˈjuzd/

Unused

未使用の; 使われていない
Meaning
not being used; not having been used before
Example
There are many unused rooms in this old mansion.
この古い館には未使用の部屋がたくさんあります。
C1 adjective /ʌnˈsaɪtli/

unsightly

見苦しい
Meaning
Unpleasant to look at; ugly.
Example
The garbage pile created an unsightly view in the park.
ゴミの山は公園に見苦しい景色を作り出した。
C1 verb /ʌnˈsɛtl/

unsettle

動揺させる
Meaning
To disturb or make someone feel anxious or uneasy.
Example
The sudden news unsettled the entire community.
突然のニュースはコミュニティ全体を動揺させた。
B2 adjective /ʌnˈlɪmɪtɪd/

unlimited

無制限
Meaning
without any limits or restrictions
Example
The internet plan offers unlimited data for the whole month.
インターネットプランは1ヶ月間の無制限データを提供します。
C1 adjective /ˌʌnəˈdɔːrnd/

unadorned

シンプルな、飾りのない
Meaning
Plain and simple; not decorated.
Example
The room was unadorned, with only a table and a chair.
部屋はシンプルで、テーブルと椅子だけがありました。
B2 adverb /ʌnˈdaʊtɪdli/

undoubtedly

間違いなく
Meaning
without a doubt, certainly
Example
He is undoubtedly the best player on the team.
彼は間違いなくチームで一番の選手です。
C2 noun /ˈʌp.wel.ɪŋ/

upwelling

湧昇流
Meaning
An oceanographic phenomenon that involves wind-driven motion of dense, cooler, and nutrient-rich water towards the ocean surface.
Example
Upwelling brings nutrients to the ocean surface.
湧昇流は海面へ栄養分を運ぶ。
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.
このツールの有用性はプロジェクト中に明らかになりました。
C1 verb /ʌnˈrævəl/

unravel

Meaning
To undo twisted or knitted threads; to solve or explain something complicated.
Example
The detective worked hard to unravel the mystery.
B1 adjective /ʌnˈsɜːrtən/

Uncertain

不確か
Meaning
not able to be relied on; not known or definite; not having reliable knowledge
Example
I am uncertain about my future career plans.
私は自分の将来のキャリア計画に不確かさを感じています。
B1 adjective /ʌnˈplɛz.ənt/

Unpleasant

不快な
Meaning
not giving or causing pleasure; disagreeable
Example
The medicine had an unpleasant taste.
その薬は不快な味がしました。
C1 adjective /ʌnˈkɛmpt/

unkempt

だらしない
Meaning
Having an untidy or disheveled appearance.
Example
He looked unkempt after sleeping outdoors all night.
彼は一晩外で寝た後、だらしなく見えた。
B2 adjective /ʌnˈdʒʌst/

Unjust

不当な; 不正な
Meaning
not fair or right; morally wrong
Example
The punishment was unjust for such a minor offense.
その罰は軽微な違反に対して不当でした。
C1 adjective /ˌʌnəˈkaʊntəbl/

unaccountable

説明できない
Meaning
Not able to be explained or justified.
Example
She felt an unaccountable fear as she entered the dark room.
彼女は暗い部屋に入ると説明できない恐怖を感じた。
B2 adjective /ˌʌndɪˈveləpt/

Undeveloped

未開発; 未成熟; 原始的
Meaning
not yet developed; immature or primitive
Example
The undeveloped land was later turned into a park.
未開発の土地は後に公園に変わりました。
C2 noun /ˈɜːrtʃɪn/

urchin

路上の子供
Meaning
a mischievous or poorly dressed child, often from the streets
Example
The ragged urchins played by the riverbank.
ぼろぼろの服を着た路上の子供たちが川辺で遊んでいた。
C2 adjective /ˌʌn.rɪˈdʒɛn.ər.ət/

unregenerate

頑固
Meaning
Not reformed or showing no signs of change; stubbornly refusing to reform or repent.
Example
He remained an unregenerate opponent of progress.
彼は進歩の頑固な反対者であり続けた。
B1 adverb /ʌnˈfɔːrtʃənətli/

Unfortunately

残念ながら
Meaning
used to express regret or disappointment about something
Example
Unfortunately, the weather was bad for our picnic.
残念ながら、私たちのピクニックには天気が悪かった。
C1 adjective /ʌnˈkwaɪ.ət/

Unquiet

落ち着かない; 不安な; 動揺した
Meaning
restless; unable to remain still or quiet; anxious or troubled
Example
She spent an unquiet night worrying about the exam results.
彼女は試験結果を心配して落ち着かない夜を過ごした。
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.
その会社は先月、売上の改善を経験しました。
C1 verb /ˌʌndərˈvæljuː/

undervalue

過小評価する
Meaning
To assign too low a value or importance to something or someone.
Example
She felt that her boss consistently undervalued her contributions.
彼女は自分の上司が彼女の貢献を一貫して過小評価していると感じていた。
C1 noun /ˌjuːnɪˈfɔːrməti/

Uniformity

均一性; 一貫性; 同一状態
Meaning
the quality of being uniform; consistency or sameness
Example
The uniformity of the design created a pleasing visual effect.
デザインの均一性が魅力的な視覚効果を生み出しました。
B2 adjective /ʌnˈstɛdi/

unsteady

不安定な
Meaning
not firm or stable; likely to change or fail
Example
She felt unsteady on her feet after the long journey.
長旅の後、彼女は足元が不安定だった。
C2 verb /ˌʌndərˈɡɜːrd/

undergird

支える、強化する
Meaning
to provide support or foundation for; to strengthen
Example
Strong values undergird a healthy society.
強い価値観は健康な社会を支えています。
B2 adjective /ˌʌnəˈweər/

Unaware

無自覚; 知らない; 気づかない
Meaning
not knowing or realizing; having no knowledge of something
Example
She was completely unaware of the danger.
彼女はその危険に完全に気づいていなかった。
A2 verb /ʌpˈset/

upset

困らせる
Meaning
to make someone worried, sad, or angry; to disturb
Example
The bad news upset everyone.
悪いニュースはみんなを upset した。