How to say "precedent" in Japanese

• 事例じれいCommon
  no-adjectiveCovers 'case; example' first and foremost: an instance or case reported or discussed, as in business or law. It only weakly carries the sense of 'precedent' and is not the usual word when you mean an earlier decision that sets a rule.
  これこそ適切てきせつな事例じれいだと思おもう。↗

  I believe this is a case in point.
• 前例ぜんれいJLPT N1approx.Common
  nounThe core word for 'precedent': an earlier instance or decision that later cases follow or are judged against. Typical in set phrases meaning 'without precedent' or 'there is no precedent for this'.
  このような問題もんだいの前例ぜんれいはない。↗

  There is no precedent for such a case.
• 実例じつれいJLPT N2approx.Common
  nounChiefly 'example; illustration': a concrete, actual instance cited to demonstrate or prove something. The 'precedent' sense listed is marginal; this is seldom the word you want for an authoritative earlier case.
  実例じつれいは教訓きょうくんにまさる。↗

  Example is better than precept.
• 先例せんれいCommon
  nounA close synonym of 前例 for 'precedent', stressing the earlier instance as a model or basis for later action. Common in contexts such as 'there is no precedent' or 'set a precedent'.
  そんな先例せんれいはない。↗

  We have no such example.
• 慣例かんれいJLPT N1approx.Common
  nounFocuses on 'custom; convention': a practice that has become established and is followed as a matter of course. Use it for the resulting established practice rather than for the single earlier case itself.

For a true sense of 'precedent' (an earlier case serving as a model or justification), 前例 and 先例 are the core choices; 慣例 emphasizes established custom, while 事例 and 実例 are mainly 'example, case'.

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

• 事例じれいexample
• 前例ぜんれいprecedent
• 実例じつれいexample
• 先例せんれいprecedent
• 慣例かんれいcustom
• 例ためしprecedent
• 儀範ぎはんprecedent
• 前蹤ぜんしょうprecedent
• 先蹤せんしょうtraces of a predecessor's deeds
• 例れいprecedent
• 定例ていれいestablished usage