infight

infight means an internal battle; a fight with allies or other members of the same group. Lexicurio rates it Sui generis — a strength score of 88 out of 100.

Etymology

Apparently a back-formation from infighting, perhaps continuing Middle English infighten (“to attack”), from Old English infiht, infeoht (“an attack made upon a person by another in the same house or between members of a household”), equivalent to in- + fight. Compare Middle English infiht (“an internal fight, a brawl within a household”).

noun

An internal battle; a fight with allies or other members of the same group.“The power struggle to establish Kim Il Sung as the sole leader in North Korea took almost a decade, entailing a series of bitter factional infights.”

verb

To fight with allies or other members of the same group.“While Kennedy infought to trim outlays to match resources, critics claimed that the era of the big eleemosynaries had come to an end.”
To box while extremely close to an opponent“Be prepared to slip and duck his jab to infight or to counter with a quick punch to the head or body.”