flap-jaw
1. Someone prone to talking a lot or at length. Good luck getting out of here—Aunt Louise is a real flap-jaw and could easily blather to you for an hour. A: "I'm sorry you had to listen to my mom ramble on like that." B: "Ah, I'm used to it—my mom's a total flap-jaw too." Oh boy, my daughter's been a flap-jaw ever since she learned to talk. Just constant chatter all the time!
2. Someone who too readily shares information, especially that which is private or confidential. Some flap-jaw has been talking to the press about our new product. Needless to say, if I find out who it is, they will be fired on the spot. If you've got a secret, don't tell it to a flap-jaw like Marty! Now I'm in trouble, thanks to you being a flap-jaw and blurting out that I got home past curfew last night!
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.