See definition of under-ground on Dictionary.com

synonyms for under-ground

On this page you'll find 300 synonyms, antonyms, and words related to under-ground, such as: classified, covert, furtive, hush-hush, mysterious, and obscure.

antonyms for under-ground

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Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

How to use under-ground in a sentence

  • Factories a long way under ground, behind the Soviet lines, factories that had once made atomic projectiles, now almost forgotten.

    Second Variety | Philip Kindred Dick
  • Perrier, to avoid these inconveniences, made an under-ground passage, by which his guest could pass to an outhouse.

  • We may make our get-away to the East, or we may stop here for good—under ground.

    Hidden Gold | Wilder Anthony

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