Translation guide
The English word 'arbitrary' can be tricky to translate directly into Japanese. It often describes decisions, rules, or choices that are random, based on personal whim, or lacking a clear reason. This guide covers natural ways to express these nuances.
Describing a decision, selection, or action that seems random, capricious, or without a logical basis.
Means 'optional' or 'voluntary', often used when something is left to one's discretion. It can imply 'arbitrary' in the sense of 'not fixed by rules'. Common in formal contexts.
参加は任意です。
Participation is arbitrary (optional).
任意の数を選んでください。
Please choose an arbitrary number.
Directly means 'arbitrary' in the sense of 'based on personal whim or bias, not on objective criteria'. Often has a negative connotation of being unfair or capricious.
その決定は恣意的だ。
That decision is arbitrary.
恣意的なルールは不公平だ。
Arbitrary rules are unfair.
Means 'whimsical' or 'capricious'. Used for actions or decisions that are impulsive and changeable, like an arbitrary choice made on a whim.
彼の気まぐれな決定に振り回された。
We were at the mercy of his arbitrary decisions.
Means 'nonsensical' or 'random'. Implies something is arbitrary in a haphazard, illogical way. Often used for random guesses or made-up rules.
でたらめな数字を言わないで。
Don't just say an arbitrary number.
Can mean 'appropriate' but also 'random' or 'half-hearted' depending on context. When used negatively, it implies an arbitrary, careless choice.
Can also mean 'suitable' in positive contexts. Tone and situation determine meaning.
適当に選んだ。
I chose arbitrarily (without much thought).
Describing a choice or action that is left to individual judgment, without a predetermined standard.
As above, but here emphasizing the 'discretionary' aspect. Common in instructions or settings.
任意の値を入力してください。
Please enter an arbitrary value.
Means 'free' or 'unrestricted'. Can convey 'arbitrary' when emphasizing lack of constraints.
自由に選んでいいよ。
You can choose arbitrarily (freely).
Used in technical contexts to describe a variable, constant, or choice that is not specified.
The standard mathematical term for 'arbitrary'. Used in phrases like 'arbitrary constant' or 'arbitrary value'.
任意の定数Cとする。
Let C be an arbitrary constant.
任意のxについて成り立つ。
It holds for an arbitrary x.
任意 (にんい) is neutral and often means 'optional' or 'at one's discretion'. 恣意的 (しいてき) is explicitly negative, implying unfairness or bias. Use 恣意的 when criticizing a decision as arbitrary and unjust; use 任意 for neutral contexts like settings or math.
There is no single Japanese word that covers all uses of 'arbitrary'. Translating it as 任意 in every case can sound unnatural. Consider the nuance: random whim (気まぐれ, でたらめ), discretionary (任意, 自由), or unfair bias (恣意的).