late 14c., from Old French collusion, from Latin collusionem (nominative collusio) "act of colluding," from colludere, from com- "together" (see com-) + ludere "to play," from ludus "game" (see ludicrous). "The notion of fraud or underhandedness is essential to collusion" [Fowler].[collusion etymology, collusion origin, 英语词源]