late 14c., endetted "owing money," past participle of endetten "to indebt, oblige," from Old French endetter "to involve in debt," from en- "in" (see in-(2)) + dette "debt" (see debt). Figurative sense of "under obligation for favors or services" first attested 1560s. Related: indebt; indebtedness. Latin indebitus meant "not owed, not due."