defile, sully, corrupt, taint, cloud -- (place under suspicion or cast doubt upon; "sully someone's reputation")
tarnish, stain, maculate, sully, defile -- (make dirty or spotty, as by exposure to air; also used metaphorically; "The silver was tarnished by the long exposure to the air"; "Her reputation was sullied after the affair with a married man")
defame, slander, smirch, asperse, denigrate, calumniate, smear, sully, besmirch -- (charge falsely or with malicious intent; attack the good name and reputation of someone; "The journalists have defamed me!" "The article in the paper sullied my reputation")