How to say "doubtful" in Japanese

• 疑わしいうたがわしいCommon
  i-adjectiveCovers doubtful in the sense of open to question: a statement, explanation, or piece of evidence whose truth or reliability you doubt. The most direct choice for intellectual, fact-based doubt.
  彼かれが時間じかんどおり来くるかどうかは疑うたがわしいと思おもう。↗

  I doubt if he will come on time.
• 怪しげあやしげCommon
  na-adjective, nounDoubtful in the sense of shady or fishy-looking: it describes the suspicious air something gives off, a dubious look or manner. Think of a scheme or operation that simply seems untrustworthy.
  怪あやしげな手てつきで彼女かのじょはグラスを運はこんできた。↗

  She fumbled with the glasses as she brought them in.
• あやふやJLPT N1approx.Common
  na-adjectiveThis is the vague, undecided side of doubtful rather than the suspicious side: answers, plans, or memories that are fuzzy and left unclear. It points to vagueness, not 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.
• 怪しいあやしいJLPT N2approx.Common
  i-adjectiveA broad word: doubtful as fishy or suspicious about someone or something, and also unsure in the sense of unreliable — information, or your own memory, that may not hold up.
  彼かれが時間じかんどおりに来くるかどうかは私は怪あやしいと思おもう。↗

  I question whether he'll come in time.

Use 「疑わしい」 when you doubt a claim's truth, 「怪しげ」 for a suspicious outward appearance, 「あやふや」 for vague, undecided matters, and 「怪しい」 for something that seems fishy or unreliable.

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

• 疑わしいうたがわしいdoubtful
• 怪しげあやしげquestionable
• あやふやuncertain
• おぼつかないuncertain
• 訝しいいぶかしいsuspicious
• 真偽不明しんぎふめいdubious
• いぶかしげquizzical
• 怪しいあやしいdoubtful
• 微妙びみょうdoubtful
• 危ないあぶないuncertain