blabbermouth
/ˈblæbərˌmaʊθ/
noun
- A person who talks too much, especially one who reveals secrets or private information.
- Don't tell her anything personal; she's a total blabbermouth.
- My little brother is such a blabbermouth — he told Mom about the surprise party.
- The team's loss was blamed on a blabbermouth who leaked the strategy to the press.
Synonyms