How to say "negligence" in Japanese

Choosing the right word
  • 油断ゆだんJLPT N2approx.Common
    noun, suru verb, intransitive verbCovers negligence as a lapse in attention — letting your guard down or being caught unprepared. Typical when an accident or mistake happens because someone was momentarily off guard, not because duties were ignored.
    私は油断ゆだんしていたことに気きづいた。↗
    I realized I was off my guard.
  • 怠慢たいまんJLPT N1approx.Common
    noun, na-adjectiveNegligence in the sense of neglect of duty: failing to do what one is responsible for. Suits criticism of a person or organization that has neglected its obligations.
    彼かれは義務ぎむ怠慢たいまんで非難ひなんされた。↗
    He was blamed for neglect of duty.
  • 怠りおこたりCommon
    nounThe act of neglecting something one ought to do — a duty, task, or effort left undone. Overlaps with 怠慢, and fits negligence as continuing neglect rather than a single careless slip.
  • 不行き届きふゆきとどきCommon
    na-adjective, nounNegligence as care or arrangements falling short — something not attended to thoroughly. Typical in apologies or complaints about imperfect service, handling, or preparation.
  • noun, na-adjectiveReally 'disregard' or 'making light of' something — treating it as unimportant — rather than negligence as a lapse or failure, and seldom the word you want for negligence itself.
    彼かれらは自分じぶんたちの義務ぎむをなおざりにはしなかった。↗
    They didn't neglect their own duty.

Choose 油断 for a momentary lapse of attention, 怠慢 for neglect of duty, 「怠り」 for the act of neglecting what one should do, 「不行き届き」 for care or arrangements falling short, and 「なおざり」 for treating things lightly.

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

Japanese equivalents
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JLPT vocabulary levels are community estimates, not official (no official lists have been published since the 2010 revision).

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