late 14c., recusen, "to decline, refuse," especially "reject another's authority or jurisdiction over oneself as prejudiced," from Old French recuser (13c.) and directly from Latin recusare "make an objection against; decline, refuse, reject; be reluctant to," from re- (see re-) + causa (see cause (n.)). Specifically, in law, "reject or challenge (a judge or juror) as disqualified to act." The word now is used mostly reflectively. Related: Recused; recusing; recisative.