How to say "intervention" in Japanese

• 介入かいにゅうJLPT N1approx.Common
  noun, suru verb, intransitive verbThe default choice for intervention: stepping into a situation, dispute, or affairs to influence the outcome, as by a government, military, or other outside party.
  このテーマに関かんするほとんどの研究けんきゅうでは、立法府りっぽうふの介入かいにゅうが悪影響あくえいきょうをもたらしたということが示しめされている。↗

  It has been shown in most studies on this subject that intervention of the legislature had adverse effects.
• 干渉かんしょうJLPT N1approx.Common
  noun, suru verb, intransitive verbInterference or meddling; intervention with an intrusive, unwelcome nuance, as when someone interferes in another person's affairs or a state meddles in another's internal matters.
  僕ぼくのことに干渉かんしょうしないでくれ。↗

  Don't interfere in my affairs.
• 介在かいざいCommon
  noun, suru verb, intransitive verbIntervention in the sense of something existing or coming between two parties, such as a third party standing between disputants; often leans toward the literal 'interposition' sense.
• 口利きくちききCommon
  nounIntervention as informal mediation or good offices: using one's connections or influence to help settle a matter behind the scenes. Rarely the right word for intervention in general.

Choose 介入 for active intervention in a situation, 干渉 for unwelcome meddling, 介在 for something standing between parties, and 「口利き」 for informal behind-the-scenes mediation.

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

• 介入かいにゅうintervention
• 干渉かんしょうinterference
• 介在かいざいexisting (between)
• 口利きくちききmediation