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English definition of “underground”


adjective, adverb (SECRET)    /ˌʌn.dəˈɡraʊnd/ US  /-dɚ-/
describes an activity that is secret and usually illegal : an underground newspaper / movement The Communist Party was forced (to go) underground, and its leaders went into hiding .Secrecy and privacyLegal and illegal
(Definition of underground adjectiveadverb (SECRET) from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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