collusion (n.) Look up collusion at Dictionary.com
late 14c., from Old French collusion, from Latin collusionem (nominative collusio) "act of colluding," from colludere, from assimilated form of com "with, together" (see com-) + ludere "to play" (see ludicrous). "The notion of fraud or underhandedness is essential to collusion" [Fowler].