WordWeb Online

1. Someone who gossips indiscreetly
   - tattler, taleteller, talebearer, telltale, blabbermouth [informal], blabber [informal]
    
2. [US, informal] Someone who reports another person's wrongdoings to someone in authority
   "I told the teacher that I'm not a tattletale and didn't want to get involved";
   - telltale [Brit, informal], grass [Brit, informal], snitch [informal], talebearer [archaic], rat [informal], squealer [informal]

Derived forms: tattletales

Type of: betrayer, blabber [informal], gossip, gossiper, gossipmonger, informer, newsmonger, rat [informal], rumormonger [US], rumourmonger [Brit, Cdn], squealer

Encyclopedia: Tattletale