# mouth off

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/mouth-off
Updated: 2026-10-22

## Definition

to speak in a rude or disrespectful way, especially to someone in charge. You use this when someone is complaining loudly or being impolite.

For teachers: To speak insolently or indiscreetly, typically to an authority figure. The verb is intransitive and often carries a connotation of aggressive or uncalled-for verbal defiance.

## Examples

- Don't mouth off to your boss if you want to keep your job.
- The teenager got into trouble for mouthing off to the police officer during the traffic stop.
- Despite the gravity of the situation, he couldn't resist mouthing off to the judge, which resulted in a harsher sentence for contempt of court.

## Pitfalls

- Not "He mouthed off his teacher." but "He mouthed off to his teacher." — The verb is intransitive; you must use the preposition 'to' before the person being addressed.

## Usage notes

- Often followed by the preposition 'to' when mentioning the person being addressed.
- Teaching tip: Contrast with 'talk back'; while both involve disrespect, 'mouth off' often implies a louder, more public, or more aggressive display of insolence.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.