(intransitive, slang) To complain or otherwise express oneself in a loud, immoderate manner. / (transitive, intransitive, slang) To talk impudently, especially to one's superior.

Third-person singular simple present indicative form of mouth off

simple past tense and past participle of mouth off

present participle of mouth off

(slang) To make reckless or exaggerated statements.

present participle of shoot one's mouth off

Third-person singular simple present indicative form of shoot one's mouth off

simple past tense and past participle of shoot one's mouth off

Alternative form of run off at the mouth