Webster's Revised Unabridged Dictionary · 1913

infighting

infighting , noun

[in- + fighting.]

[Such infighting may lead to factionalism.]

1.
contention among members of the same organization (usually concealed from outsiders), sometimes of a bitter, intense, or prolonged character.
2.
fighting, such as boxing, at close quarters.
3.
rough-and-tumble, free-for-all fighting.