Melee
Chaotic Battle
noun
A riot of war is where things go nuts. This is a melee!
乱戦 refers to a chaotic battle. It can describe actual warfare, sports matches, or other competitive scenarios where things become tumultuous and disorganized.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
あの試合はまれに見る乱戦だった。
That game was a free for all that we don't see very often.
ちょっと乱戦気味になったけど、勝てたからオールオッケー！
Things turned into a bit of a free-for-all, but since we won, it's all good!
セール初日、モールは人でごった返しになり、まるで大乱戦のようだった。
On the first day of the sale, the mall became super crowded, like it was some kind of battle royal.