Did you know?

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

slack - 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.

adjective     slack pronunciation in British English
Word Forms
  1. 1
    loose and not pulled tight

    The fence consisted of two slack strands of barbed wire.

    The rope suddenly went slack.

    Her muscles felt slack.

  2. 2
    not taking enough care to make sure that something is done well

    Some slack defending allowed Valencia to score another goal.

  3. 3
    not as busy or successful as usual in business

    Business is usually slack in the winter.

    Demand for the product is slack.

derived word


noun [uncountable]

deep learning

a form of machine learning which incorporates the use of neural networks

BuzzWord Article

Word of the Day


meat from a young cow

Open Dictionary

snap election

a general election … that is called earlier than expected

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