Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “underground”

See all translations

underground

adjective, adverb uk   /ˌʌn.dəˈɡraʊnd/ us    /-dɚ-/

underground adjective, adverb (BELOW EARTH)

B2 below the surface of the Earth; below ground: an underground cave/passage/cable Moles live underground.
More examples

underground adjective, adverb (SECRET)

An underground activity is secret and usually illegal: an underground newspaper/movement The Communist Party was forced (to go) underground, and its leaders went into hiding.

underground

noun uk   /ˈʌn.də.ɡraʊnd/ us    /-dɚ-/

underground noun (TRANSPORT)

the underground A2 [S] ( also the tube) UK a railway system in which electric trains travel along passages below ground: the London Underground They went on the underground.

underground noun (PEOPLE)

[U] people in a society who are trying new and often shocking or illegal ways of living or forms of art: In Britain and the USA in the 1970s, the underground was a powerful subversive force.the underground a group of people who secretly fight against the government: He was a member of the underground, harassing the invading army.
(Definition of underground from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of underground?
Add Cambridge dictionaries to your browser to your website

Definitions of “underground” in other dictionaries

Word of the Day

justice

fairness in the way people are dealt with

Word of the Day

A certain je ne sais quoi: French words and phrases used in English

by Liz Walter,
January 21, 2015
It is an odd irony that the more sophisticated your use of English is, the more likely you are to use French words and phrases. Or, to be more accurate, ones you know to be French – words such as ballet, au pair, abattoir, fiancé, café, and restaurant are so entrenched in

Read More 

flower beard noun

January 19, 2015
a beard adorned with flowers And some of said beard-rockers are even turning it up a notch, painting trend on top of trend with what’s come to be known as ‘the flower beard.’

Read More