Did you know?

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

mad - 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.



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.

adjective mad pronunciation in British English /mæd/
Word Forms
  1. 1
    very silly or stupid
    You’ll think I’m mad – I’ve just left my job.
    be mad to do something: You’re mad to spend so much money on clothes.
    1. a.
      informal tending to behave in a strange way that other people sometimes consider funny
      a mad scientist
      Synonyms and related words
    2. b.
      informal an offensive way for describing someone who is mentally ill
      She was completely mad.
      Synonyms and related words
  2. 2
    [never before noun] informal angry
    He makes me mad, the way he keeps criticizing me all the time.
    mad at/with: My boss is mad with me for missing the meeting.
    Synonyms and related words
  3. 3
    done quickly or without thinking, in a way that is badly organized
    There were people everywhere – it was all a bit mad!
    a mad rush/dash: It was a mad rush to get the job finished.



… a feeling of pleasure you get from spending time doing what you want and not worrying about what other people are doing or saying

BuzzWord Article

Word of the Day


lively or active

Open Dictionary

brain fade

a temporary inability to think clearly or remember information

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