flap-jaw

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.
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!
Farlex Dictionary of Idioms.
See also:
  • flapjaw
  • goofball
  • goofer
  • prone to
  • be in a flap
  • flap (one's) chops
  • flap (one's) gums
  • flap gums
  • flap your gums
  • come to a climax