How to say "unreliable" in Japanese

• 頼りないたよりないCommon
  i-adjectiveFor people or things you cannot lean on: a person who seems weak or timid, or light, support, or hope that feels faint. Picture a colleague you hesitate to trust with an important task.
• 不確かふたしかCommon
  na-adjective, nounUnreliable in the sense of uncertain or unclear: information, memory, or evidence that cannot be fully trusted because it is vague or unsettled. Typical context: acting on secondhand information you are not sure of.
  結果けっかはまだ不確ふたしかである。↗

  The result is still in doubt.
• 不確実ふかくじつCommon
  na-adjective, nounCovers uncertainty about outcomes or truth: prospects, evidence, or information that offer no guarantee. It stresses that something cannot be counted on. Typical context: planning around an uncertain future.
  ネット上じょうの不ふ確実かくじつな情報じょうほうを鵜呑うのみにしてはならない。↗

  You mustn't swallow unreliable information that's on the Web.
• 危なっかしいあぶなっかしいCommon
  i-adjectiveReally means looking dangerous or precarious; as 'unreliable' it fits someone or something that seems about to fail or go wrong. Typical context: watching a nervous beginner's driving or a shaky-looking ladder with anxiety.
• 適当てきとうJLPT N4approx.Common
  na-adjective, nounIts core sense is perfunctory or sloppy: work done carelessly, answers given offhand. It describes an attitude rather than dependability itself, so use it for unreliability that comes from not taking things seriously.

Choose 「頼りない」 for people or things you cannot lean on, 「不確か」 or 不確実 for uncertain information and outcomes, 「危なっかしい」 for what looks dangerously precarious, and 適当 for careless, sloppy attitudes.

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

• 頼りないたよりないunreliable
• 不確かふたしかunreliable
• 不確実ふかくじつuncertain
• 危なっかしいあぶなっかしいdangerous
• あてにならないunreliable
• いかがわしいsuspicious
• 危なかしいあぶなかしいdangerous
• 危ないあぶないuncertain
• 怪しいあやしいuntrustworthy
• 適当てきとうperfunctory
• 心もとないこころもとないunreliable
• おぼつかないunreliable
• ぽんこつclumsy