arbitrary
arbitrary はTOEFL 60・IELTS 5.5レベルの英単語で、「恣意的な、独断的な、任意の」という意味があります。発音記号は /ˈɑːrbɪtreri/ です。
意味一覧 (2件)
恣意的な、独断的な
解説 Definition
人や組織が、明確な基準や公平な手続きではなく、自分の判断や都合だけで物事を決めるときに使う。法律・行政・ルール運用などで「根拠が弱く、不公平だ」と批判的に述べる文脈でよく現れる。単に自由に選べるという意味ではなく、勝手で一貫性を欠くという否定的な響きが強い。
Arbitrary describes a decision, rule, or action that is based on someone's personal choice rather than clear reasons, fair procedures, or consistent standards. It is often used critically in contexts such as law, government, or management, where a weak or unfair basis is a problem. In some fields like mathematics, arbitrary can also mean "any chosen" rather than "unfair," so the meaning depends on the context.
覚え方のコツ Memory Tip
まず中にある art を見ても「芸術」とは結びつけず、むしろ “人の判断で形が決まる語” と覚えると整理しやすいです。arbitrary decision なら、ルールや根拠より決める側の都合が前に出た「恣意的な決定」。一方で mathematics などの arbitrary number は「どれでもよい任意の数」。文脈で「勝手な」と「任意の」が分かれる語なので、arbitrary choice / arbitrary rule のような組み合わせごと覚えると混同しにくいです。
When you see the art inside arbitrary, do not connect it to "art." It is more useful to think of the word as something shaped by a person's judgment. An arbitrary decision is one made more by someone's convenience than by rules or good reasons, but in mathematics an arbitrary number simply means any number chosen. Learning common pairs like arbitrary decision, arbitrary rule, and arbitrary number will help you keep these meanings separate.
例文
The court said the agency's arbitrary decision was unfair and had no clear legal basis.
裁判所は、その機関の恣意的な決定は不公平で法的根拠も明確でないと述べた。
Employees were frustrated by the manager's arbitrary rules, which seemed to change from week to week.
従業員たちは、週ごとに変わるように見える上司の独断的なルールに不満を感じていた。
In this formula, x can be an arbitrary number, as long as it is greater than zero.
この式では、x は0より大きければ任意の数でよい。
任意の
(意味 2)解説 Definition
何の根拠もなく、勝手に決められた。ランダムに、または規則性のなく選ばれること。
Arbitrary means based on personal choice, chance, or no clear reason, rather than on a fixed rule or system. It is often used when a decision seems random or unfair. In technical contexts, it can also mean any value chosen without a special limit.
覚え方のコツ Memory Tip
arbitrary は数学・論理・技術文脈では「任意の」として使われます。an arbitrary number や an arbitrary point は、特定の数や点を指すのではなく、条件を満たすものならどれを選んでもよいということです。証明や説明で「一つを自由に選んでも一般性を失わない」感覚を表します。日常語の arbitrary decision のような不公平さではなく、固定された値に縛られない選択として覚えると整理しやすいです。
In math or logic, arbitrary often means any one you choose. An arbitrary number or an arbitrary point is not fixed in advance, but it must fit the conditions. The key idea is free choice within a rule, not unfair decision-making.
例文
The selection process seemed arbitrary and unfair.
その選出プロセスは恣意的で不公平に見えた。
The arbitrary rules of the game confused the players.
そのゲームの恣意的なルールはプレイヤーを困惑させた。
His decision appeared arbitrary with no logical explanation.
彼の決定は論理的な説明がなく恣意的に見えた。
arbitrary の語源・成り立ち Etymology
arbitrary はラテン語 arbitrarius「判断にゆだねられた」に由来し、さらに arbiter「裁定者・審判者」へさかのぼります。語根 arbitr- は「判断する人」の感覚で、もとは「審判の裁量次第の」が、今の「任意の・勝手な」につながります。関連語は arbiter、arbitration です。
Arbitrary comes from the Latin word arbitrarius, meaning "depending on judgment," and it is related to arbiter, meaning "judge" or "decider." The original idea was "left to someone's decision," which later developed into the modern meanings "chosen freely" and "decided in a possibly unfair or inconsistent way."
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