How to say "dubious" in Japanese

• 怪しいあやしいJLPT N2approx.Common
  i-adjectiveCovers 'dubious' in the sense of suspect or shady: a deal, story, or person that arouses suspicion. It implies you actively distrust the thing described.
  みんな奴やつは怪あやしいと思おもっている。↗

  We are all suspicious about him.
• 半信半疑はんしんはんぎCommon
  no-adjectiveDescribes the doubter rather than the thing doubted: you take a claim or story half in doubt, half convinced. A four-character idiom for being dubious about what someone tells you.
  ああ、オレも実際じっさい、こうして目の当まのあたりにするまでは半信はんしん半疑はんぎだったが・・・。↗

  Yes, truthfully, until it was right in front of me like this, I half-doubted it ...
• あやふやJLPT N1approx.Common
  na-adjectiveSeldom the word you want for 'dubious': it really means vague, uncertain, or ambiguous, as with a fuzzy answer or an unclear memory, not something that arouses suspicion.
  あやふやな手てつきで一いち枚まいの紙かみを動うごかした。↗

  She fumbled with a piece of paper.

Use 「怪しい」 for things that arouse suspicion, 半信半疑 for a person who half believes and half doubts something, and 「あやふや」 only when 'dubious' really means vague or unclear.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 怪しいあやしいsuspicious
• 半信半疑はんしんはんぎhalf in doubt
• あやふやuncertain
• 真偽不明しんぎふめいdubious
• 訝しいいぶかしいsuspicious
• いかがわしいsuspicious
• いんちき臭いいんちきくさいfishy
• 怪訝けげんpuzzled
• 胡散臭いうさんくさいsuspicious-looking
• きな臭いきなくさいsuspicious