mouth off

English edit

mouth off (third-person singular simple present mouths off, present participle mouthing off, simple past and past participle mouthed off)

(intransitive, slang) To complain or otherwise express oneself in a loud, immoderate manner.
(transitive, intransitive, slang) To talk impudently, especially to one's superior.
- 2008, “Play It Again, Brian”, in Family Guy, Herbert (actor):
  And don't you mouth off to me, or I'm gonna slap you right in your penis.

to complain or otherwise express oneself in a loud, immoderate manner

to talk impudently, especially to one's superior