How to say "breach" in Japanese

• 攻め込むせめこむCommon
  godan verb, intransitive verbCovers 'breach' only in the sense of invading: forcing one's way into enemy territory or through an opponent's defense. It is essentially a verb of attack, not a general word for breach.
• 決壊けっかいCommon
  noun, suru verb, transitive verb, intransitive verbThe physical breach of a dam, embankment, or levee: the structure bursts and water breaks through. Use it for this engineering-disaster sense, not for breaches of rules or agreements.
  大雨おおあめのためにダムが決壊けっかいした。↗

  The dam burst owing to the heavy rain.
• 違反いはんJLPT N3approx.Common
  noun, suru verb, intransitive verbBreach in the legal or contractual sense: violating a law, contract, or formal rule. When English 'breach' means an offense against such obligations, this is the natural choice.
  相あい次つぐ不祥事ふしょうじにも関かかわらず、警察けいさつはオメオメ違反いはん切符きっぷを切きっている。↗

  Despite their own scandals, the police continue to make arrests as though nothing had happened at all.
• 破るやぶるJLPT N3approx.Common
  godan verb, transitive verbTo breach in the sense of breaking through something physical: a cordon or an opponent's defense. Use it when someone forces a way past a barrier or defensive line.
• 反則はんそくCommon
  noun, suru verb, intransitive verbBreach as infringement of rules or regulations, often in games and sport, where it amounts to a foul or infraction. For rule-breaking in a match or under regulations, this fits.

For a burst dam or levee use 決壊; for breaking through a cordon or defense 「破る」, or 「攻め込む」 when it amounts to invading; for breach of law or contract 違反; for breach of rules or regulations 反則.

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

• 攻め込むせめこむto invade
• 決壊けっかいburst (e.g. dam, embankment, levee)
• 違反いはんviolation
• ブリーチbreach (of a whale)
• やぶれtear
• 突破口とっぱこうbreakthrough (research, etc.)
• 背反行為はいはんこういact of disobedience (betrayal)
• 破るやぶるto break through (cordon, opponent's defense, etc.)
• 反則はんそくviolation (of the law, regulations, etc.)
• 決するけっするto break and overflow (e.g. levee)