open (one's) big mouth

open (one's) big mouth

To say something that is meant to be a secret; to say something in an indiscreet, noisy, or boorish manner. Why did you have to open your big mouth about my crush on Tommy? Why couldn't you just keep it between us? We would have gotten away with the plan if she hadn't opened her big mouth!
See also: big, mouth, open
Farlex Dictionary of Idioms.
See also:
  • say (something) for (someone or something)
  • say for
  • hint at
  • hint at (something)
  • hold (one's) tongue
  • hold one's tongue
  • hold tongue
  • hold your tongue
  • Hold your tongue!
  • go further