blabber

(noun) one who reveals confidential information in return for money. Synonyms: informer, betrayer, rat, squealer.

(verb) speak (about unimportant matters) rapidly and incessantly. Synonyms: chatter, piffle, palaver, prate, tittle-tattle, twaddle, clack, maunder, prattle, blab, gibber, tattle, gabble.