How to say "unclear" in Japanese

• 不明ふめいJLPT N1approx.Common
  na-adjective, nounCovers 'unclear' when something cannot be identified or is not known — an unclear cause, reason, or whereabouts. The emphasis is on factual obscurity rather than vague wording.
• 曖昧あいまいJLPT N2approx.Common
  na-adjective, nounCovers 'unclear' in the sense of vague or ambiguous — answers, attitudes, or boundaries that are ill-defined. It often suggests a statement that avoids commitment or lacks a clear line.
  その法律ほうりつには曖昧あいまいな点てんが多おおい。↗

  That law is full of ambiguities.
• 不確かふたしかCommon
  na-adjective, nounIts core senses are 'uncertain,' 'unreliable,' and 'indefinite,' as of information or memory one cannot fully trust; 'unclear' is only a secondary shade, so it is seldom the word you want for plain 'unclear.'
  結果けっかはまだ不確ふたしかである。↗

  The result is still in doubt.
• 舌足らずしたたらずCommon
  no-adjective, na-adjectiveApplies only to unclear wording or expression: speech or an explanation that is poorly expressed, imprecise, or inadequate, leaving the point insufficiently conveyed. It is not for facts or images that are simply obscure.
  彼かれの説明せつめい、舌した足たらずでよく分わからなかった。↗

  His explanation was too sketchy. I didn't understand it.

Use 不明 for facts or things that cannot be identified or known, 曖昧 for vague or ambiguous statements, 「不確か」 mainly for uncertain or unreliable information, and 「舌足らず」 only for poorly expressed wording.

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

• 不明ふめいunclear
• 曖昧あいまいvague
• 不確かふたしかunreliable
• 不明瞭ふめいりょうunclear
• 未解明みかいめいunexplained
• 雲をつかむようくもをつかむようvague
• 暗然あんぜんdark
• 不明確ふめいかくinaccurate
• 海のものとも山のものともつかないうみのものともやまのものともつかないneither fish nor fowl
• 不透明ふとうめいunclear
• 舌足らずしたたらずpoorly expressed
• おぼつかないunclear
• ぼうぼうvague (e.g. memories)
• 舌っ足らずしたったらずpoorly expressed
• どすmuddy