confused fight; free-for-all; melee
Describes a chaotic, disorganized fight or battle where many participants are mixed together. Often used in sports, military, or metaphorical contexts.
試合は乱戦模様になった。
The match turned into a free-for-all.
In the confused fight, he lost sight of the enemy.
乱戦 describes a chaotic contest or battle, often in sports or war, with an uncertain outcome, while 乱闘 specifically denotes a physical brawl among multiple people.
battle royal; large-scale free-for-all
Compound of 乱 (ran, 'disorder') and 戦 (sen, 'battle'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a chaotic fight.