WordWeb Online

1. Speak out against
   "He denounced the Nazis";
   - denunciate
    
2. Accuse or condemn openly or formally; classify or describe as disgraceful
   "He denounced the government action";
   - stigmatize, stigmatise [Brit], brand, mark, denunciate
    
3. Announce the termination of, as of treaties
    
4. Give away information about somebody
   "He denounced his classmate who had cheated on the exam";
   - tell on, betray, give away, rat [informal], grass, shop [informal], snitch [informal], stag, squeak [informal]

Derived forms: denouncing, denounces, denounced

Type of: announce, criticise [Brit], criticize, damn [informal], denote, inform, knock [informal], label, pick apart