WordWeb Online

1. Cause to seem less serious; play down
   "Don't denigrate his influence";
   - minimize, belittle, derogate, minimise [Brit]
    
2. Charge falsely or with malicious intent; attack the good name and reputation of someone
   - defame, slander, smirch, asperse, calumniate, smear, sully, besmirch

Derived forms: denigrating, denigrated, denigrates

Type of: accuse, belittle, charge, disparage, pick at