mouth off: meaning, definition, pronunciation and examples

C1
UK/ˌmaʊθ ˈɒf/US/ˌmaʊθ ˈɔːf/

Informal, often pejorative

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Quick answer

What does “mouth off” mean?

To talk loudly, arrogantly, or disrespectfully.

Audio

Pronunciation

Definition

Meaning and Definition

To talk loudly, arrogantly, or disrespectfully; to express one's opinions in a rude or confrontational way.

To complain, boast, or argue in a loud, uncontrolled, or insolent manner, often without considering the consequences or showing respect for authority.

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning or usage. The phrase is well-understood and used in both varieties.

Connotations

Equally negative and informal in both dialects.

Frequency

Common in both, perhaps slightly more frequent in American English, especially in contexts related to defiance of authority.

Grammar

How to Use “mouth off” in a Sentence

[Subject] + mouth off + (at/to + [Person])[Subject] + mouth off + about + [Topic][Subject] + mouth off + (adverb, e.g., constantly, angrily)

Vocabulary

Collocations

strong
mouth off to the bossmouth off about the rulesmouth off at the teacher
medium
mouth off to the policemouth off in classmouth off online
weak
mouth off constantlymouth off againmouth off during

Examples

Examples of “mouth off” in a Sentence

verb

British English

  • The lad got detention for mouthing off at his maths teacher.
  • He's always mouthing off about politics in the pub.

American English

  • The player was ejected for mouthing off to the referee.
  • She mouthed off about her boss on social media and got in trouble.

adverb

British English

  • (No adverbial form.)

American English

  • (No adverbial form.)

adjective

British English

  • (No common adjectival form for the phrasal verb. Related: 'mouthy'.)

American English

  • (No common adjectival form for the phrasal verb. Related: 'mouthy'.)

Usage

Meaning in Context

Business

Highly inappropriate. 'He got fired for mouthing off to the regional director.'

Academic

Not used in formal writing; may appear in informal speech among students or staff. 'The student was disciplined for mouthing off at the professor.'

Everyday

Common in informal speech, especially regarding conflict or disrespect. 'Don't you dare mouth off to your mother like that!'

Technical

Not applicable.

Vocabulary

Synonyms of “mouth off”

Strong

sass (US)cheek (UK)be impertinentbe disrespectful

Neutral

talk backbe insolentbe rude

Weak

complain loudlyspeak out of turnsound off

Vocabulary

Antonyms of “mouth off”

be respectfulbe deferentialhold one's tonguekeep quietbe polite

Watch out

Common Mistakes When Using “mouth off”

  • Using it in formal contexts.
  • Confusing it with 'speak up' (which is positive).
  • Incorrect preposition: 'He mouthed off on the teacher' (should be 'at' or 'to').

FAQ

Frequently Asked Questions

Yes, it is almost always negative and implies rudeness, insolence, or a lack of respect.

Yes, it can be intransitive (e.g., 'He just wouldn't stop mouthing off.'). However, it often takes a prepositional phrase starting with 'to', 'at', or 'about'.

'Mouth off' specifically includes a rude, loud, or defiant attitude. You can 'complain' politely, but 'mouthing off' is never polite.

Yes, 'mouthy' (informal) describes a person who is likely to mouth off—cheeky, talkative, and disrespectful.

To talk loudly, arrogantly, or disrespectfully.

Mouth off is usually informal, often pejorative in register.

Mouth off: in British English it is pronounced /ˌmaʊθ ˈɒf/, and in American English it is pronounced /ˌmaʊθ ˈɔːf/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • Shut your mouth! (as a related imperative)
  • Big mouth (noun for someone who mouths off)

Learning

Memory Aids

Mnemonic

Imagine someone's MOUTH is so active and rude it's trying to jump OFF their face to shout at someone.

Conceptual Metaphor

DISRESPECTFUL SPEECH IS UNCONTROLLED PHYSICAL EJECTION (from the mouth).

Practice

Quiz

Fill in the gap
He was fired after he to his supervisor during the staff meeting.
Multiple Choice

What is the closest meaning of 'mouth off' in this sentence: 'The teenager mouthed off to the security guard and was asked to leave the mall.'?

Practise

Train, don’t just look up

Five interactive tools to remember words, train your ear, and build vocabulary in real context — drawn from this dictionary.

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