How to say "exhaustive" in Japanese

• 十二分じゅうにぶんCommon
  na-adjective, no-adjectiveCovers the 'exhaustive' sense only loosely, since its core meaning is 'more than enough, more than ample'. Use it for ample effort, preparation, or satisfaction rather than for an exhaustive analysis.
  彼かれは自分じぶんの役割やくわりを十二分じゅうにぶんに生いかしていますよ。↗

  He's living his role to the hilt.
• 徹底的てっていてきCommon
  na-adjectiveThe usual word for exhaustive in the sense of thorough and complete: an exhaustive investigation, search, or overhaul that leaves nothing unexamined.
  あの男おとこは徹底的てっていてきなエゴイストだ。↗

  That man is an egotist through and through.

Use 徹底的 for genuinely thorough, complete treatment of investigations or work, while 十二分 basically means 'more than enough', so it fits only when exhaustive effort or preparation is meant.

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

• 十二分じゅうにぶんmore than enough
• 徹底的てっていてきthorough
• 消耗的しょうもうてきexhaustive
• 網羅的もうらてきcomprehensive