denigrate 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. cause to seem less serious; play down
   "Don't belittle his influence"
   minimize  belittle  denigrate  derogate