Infighting comes from Middle English in- prefixed to fighting, with the prefix ultimately deriving from Latin in- and Latin in, both related to Proto-Indo-European ne, oyd-, and en.
infighting (English): Fighting or quarreling among the members of a...
Definitions
Fighting or quarreling among the members of a...
Ancestry of “infighting”, step by step
infighting traces back through two separate lines of ancestry.