1. work jointly towards the same end: "the leaders promised to cooperate in ending the civil war"
▪ assist someone or comply with their requests:"his captor threatened to kill him if he didn't cooperate"Similarcollaboratework togetherwork side by sideact togetheract jointlypull togetherband togethercome togetherget togetherjoin forcesteam upunitecombinemergeamalgamatepool resourcesclub togethermake common causeform an alliancecoordinate with each otherliaise with each otherconspireconnivecolludebe in collusionwork hand in gloveinformal:gang uprare:coactbe of assistanceassisthelplend a handbe of servicegive one's supportgive one's backingcontributechip indo one's bitthrow in one's lotparticipatetake partjoin inget involvedgo alonginformal:pitch inplay balltag alongget in on the actmuck inget stuck in
Word Originlate 16th century: from ecclesiastical Latin cooperat- ‘worked together’, from the verb cooperari, from co- ‘together’ + operari ‘to work’.
