Translation guide
The English word "dubious" covers several related meanings: expressing doubt, being questionable or suspicious, and describing something of uncertain quality or reliability. This guide breaks down these meanings and provides natural Japanese equivalents for each.
Expressing that you are not sure about something, or that you have doubts.
The most direct equivalent for 'dubious' when you feel something is doubtful or suspect. Can be used for facts, statements, or situations.
彼の説明は少し疑わしい。
His explanation is a bit dubious.
その話の真偽は疑わしい。
The truth of that story is dubious.
Literally 'to think of as a question/doubt'. A common way to say you find something dubious or questionable.
彼の動機を疑問に思う。
I find his motives dubious.
A set phrase meaning 'half-believing, half-doubting'. Used when you are skeptical but not entirely dismissive.
そのニュースには半信半疑だ。
I'm dubious about that news.
Means 'suspicious' or 'shady'. Often used for people, situations, or things that seem dubious in a more intuitive, less analytical way.
あの人はちょっと怪しい。
That person seems a bit dubious.
Describing something that is probably not good, honest, or trustworthy.
Again the most direct translation. Works for moral dubiousness, questionable practices, etc.
それは倫理的に疑わしい行為だ。
That's an ethically dubious act.
彼の経歴は疑わしい。
His background is dubious.
Overlaps with 'いかがわしい' but more colloquial. Can describe anything from a suspicious person to a dubious claim.
Describing something that may not succeed or may not be worth it.
Means 'uncertain' or 'unreliable'. Good for plans, results, or information that is dubious.
成功するかどうかは不確かだ。
Whether it will succeed is dubious.
Literally 'it's a dubious point'. Used when you are skeptical about a specific aspect.
その計画の実現性は疑わしいところだ。
The feasibility of that plan is dubious.
疑わしい (utagawashii) is the most neutral and can be used in formal contexts. 怪しい (ayashii) is more intuitive and colloquial, often implying a gut feeling of suspicion. いかがわしい (ikagawashii) specifically implies moral dubiousness or shadiness, often related to businesses or people.
While 疑わしい is a direct equivalent, Japanese often expresses doubt through phrases like 疑問に思う or 半信半疑だ. Using these can sound more natural than always defaulting to 疑わしい.
Means 'shady', 'disreputable', or 'questionable'. Often used for businesses, offers, or people that seem untrustworthy or morally dubious.
いかがわしい商売に手を出すな。
Don't get involved in dubious businesses.
彼はいかがわしい人物だ。
He's a dubious character.
怪しい儲け話には気をつけて。
Be careful of dubious money-making schemes.
Stronger than '怪しい', implies something smells fishy or is clearly dubious. Often used for people or deals.
あのセールスマンは胡散臭い。
That salesman is really dubious.
Means 'uncertain', 'unreliable', or 'not reassuring'. Often used for prospects or abilities that seem dubious.
彼の回復の見込みは心許ない。
His chances of recovery are dubious.