tattle

(noun) disclosing information or giving evidence about another. Synonyms: singing, telling.

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

(verb) divulge confidential information or secrets. Synonyms: spill the beans, let the cat out of the bag, talk, blab, peach, babble, sing, babble out, blab out. Examples: "Be careful--his secretary talks."