Did you know?

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

underground - 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.

adverb     underground pronunciation in British English
  1. 1
    below the surface of the ground

    miners who work all day underground

    Many species of beetle live underground.

    Synonyms and related words
  2. 2
    in or to a secret place away from the police or other authorities

    Left-wing activists were driven underground after the coup.

    go underground:

    The police became suspicious and he had to go underground.


Physical Cookie

a small electronic device which is taken into shops and links individual customers to advertisements …

BuzzWord Article

Open Dictionary


the act or practice of telling the future using random items such as playing cards

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