How to say "free-for-all" in Japanese

• 混戦こんせんCommon
  noun, suru verb, intransitive verbA confused fight in which many participants are jumbled together with no clear sides or order. Use it for a melee — a chaotic battle where the fighters are all mixed up together.
• 乱戦らんせんCommon
  nounMuch the same as 混戦: a disorderly battle in which many fighters are thrown together in chaos. It also covers a dogfight, so it suits an aerial free-for-all as well.
• 乱闘らんとうCommon
  noun, suru verb, intransitive verbA brawl or scuffle: a violent, disorderly physical fight that breaks out among a group of people. Its 'free-for-all' is a wild, close-quarters melee of this kind, not a large-scale battle.
  警官けいかん隊たいはデモ隊たいと乱闘らんとうになった。↗

  The police brawled with the demonstrators.

For a chaotic battle among many sides, 混戦 and 乱戦 are near-synonyms, 混戦 stressing the jumbled mingling of fighters and 乱戦 also covering dogfights, while 乱闘 is really a brawl or scuffle.

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

• 混戦こんせんconfused fight
• 乱戦らんせんconfused fight
• 乱闘らんとうconfused fight
• 参加自由さんかじゆうfree-for-all
• 自由参加じゆうさんかfree-for-all
• やりたい放題やりたいほうだいas one pleases
• 乱闘騒ぎらんとうさわぎbrawl