sully in WordNet English dictionary

1. 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"
   defame  slander  smirch  asperse  denigrate  calumniate  smear  sully  besmirch 
   
2. place under suspicion or cast doubt upon
   "sully someone's reputation"
   defile  sully  corrupt  taint  cloud 
   
3. 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"
   tarnish  stain  maculate  sully  defile