Translation guide
Expressing that something is doubtful, suspicious, or not certain in Japanese.
Expressing that the truth, quality, or outcome of something is not certain or is open to doubt.
Describing actions, decisions, or behavior that are questionable from a moral or ethical standpoint.
A clear way to say something is ethically questionable. Suitable for formal contexts.
その実験は倫理的に問題がある。
That experiment is ethically questionable.
Expressing that the quality, accuracy, or trustworthiness of something is questionable.
Directly states that the quality is questionable.
この製品は質が疑わしい。
This product is of questionable quality.
疑わしい (utagawashii) is the most neutral for 'doubtful' or 'questionable.' 怪しい (ayashii) implies suspicion or a shady atmosphere, often used for people or situations. いかがわしい (ikagawashii) is stronger, suggesting something disreputable or morally dubious, like a shady business.
彼のアリバイは疑わしい。
His alibi is questionable.
あの路地は夜は怪しい。
That alley is questionable at night.
いかがわしい広告に注意。
Beware of questionable advertisements.
The most direct equivalent for 'questionable,' meaning something is doubtful or suspicious. Often used for facts, claims, or motives.
彼の説明は少し疑わしい。
His explanation is a bit questionable.
Literally 'there is doubt,' used to say that something is questionable or open to question. More formal than 疑わしい.
その計画には疑問がある。
That plan is questionable.
Means 'uncertain' or 'unreliable.' Used when the validity or accuracy is questionable.
その情報は不確かだ。
That information is questionable.
Means 'suspicious' or 'shady.' Often used for people, situations, or things that seem questionable in a dubious sense. Can be too strong for neutral doubt.
Can imply suspicion of wrongdoing, so use carefully when you only mean 'uncertain.'
あの人はちょっと怪しい。
That person is a bit questionable.
Literally 'morally questionable.' Used in discussions of right and wrong.
彼の行動は道徳的に疑わしい。
His behavior is morally questionable.
Means 'shady,' 'dubious,' or 'disreputable.' Often used for businesses or offers that seem questionable.
Has a strong negative connotation, implying something is not trustworthy or possibly illegal.
いかがわしい商売だ。
It's a questionable business.
Means 'lacks reliability.' Used when the trustworthiness of a source or method is questionable.
そのデータは信頼性に欠ける。
That data is of questionable reliability.
Means 'unreliable' or 'not to be trusted.' Casual and often used in speech.
彼の言うことはあてにならない。
What he says is questionable.