Did you know?

Click any word in a definition or example to find the entry for that word

mouth off - definition and synonyms


What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.



Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

phrasal verb [intransitive] informal
Word Forms
present tense
I/you/we/theymouth off
he/she/itmouths off
present participlemouthing off
past tensemouthed off
past participlemouthed off
  1. to give your opinions about something in a very annoying way, especially when you are complaining or criticizing something

    He’s always mouthing off about the state of the roads.

See also main entry: mouth

Open Dictionary


a rise in the level of a stream or river

add a word


A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play