underground 1 of 3

adjective

ˈən-dər-ˌgrau̇nd How to pronounce underground (audio)
Definition of undergroundnext
1
as in clandestine
undertaken or done so as to escape being observed or known by others an underground operation to smuggle ancient artifacts out of the country

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Antonyms & Near Antonyms
2
as in subterranean
being, situated, or operating beneath the surface of the earth an underground shopping mall that is part of the city's subway system

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Antonyms & Near Antonyms

underground

2 of 3

noun

ˈən-dər-ˌgrau̇nd How to pronounce underground (audio)
as in resistance
a secret organization in a conquered country fighting against enemy forces joined the underground while still a teenager

Synonyms & Similar Words

underground

3 of 3

adverb

as in undercover

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of underground
Adjective
The result was the equivalent of an X-ray of the subsurface extending roughly 300 feet underground, without drilling a single hole. — Nolan Roth, Scientific American, 23 Aug. 2026 Once an extensive underground network of rhizomes develops, Messinger explains that complete removal becomes considerably more difficult. — Sj McShane, Martha Stewart, 23 Aug. 2026
Noun
Her work has included uncovering human trafficking networks, revealing an ISIS underground torture prison in Syria, documenting the war in Ukraine and interviewing senior political figures and world leaders. — Efrat Lachter, FOXNews.com, 30 July 2026 For the past half-decade, evilgiane and his Surf Gang collective have had their hands all over the quirkiest and most effervescent sounds of rap’s underground and mainstream. — Oba Awolowo, Pitchfork, 3 July 2026
Adverb
Meanwhile, increasingly complex deposits can require mines to operate deeper underground and adopt more demanding extraction methods. — Ariel Cohen, Forbes.com, 18 Aug. 2026 Instead of storing this platform ambient heat underground for the winter, just use it right now. — Voice Of The People, New York Daily News, 16 Aug. 2026 See All Example Sentences for underground
Recent Examples of Synonyms for underground
  1. clandestine
  2. subterranean
  3. resistance
  4. stealthily
  5. undercover
  6. surreptitiously
  7. covert
  8. clandestinely
Adjective
  • The clandestine transits have changed the game for the Middle Eastern oil industry.
    — David Goldman, CNN Money, 22 Aug. 2026
  • That same teen sensation left West Africa due to troubles from its dictatorship, and moved to Paris under cover of night and a clandestine air flight.
    — A.D. Amorosi, Variety, 18 Aug. 2026
Definition of clandestine
Adjective
  • Next year, a subterranean, London-social-club-style complex of lounges called the Bunker Suites is expected to open.
    — Ben Ryder Howe, Curbed, 21 Aug. 2026
  • The subterranean restaurant serves up some of the city’s most sophisticated noodles, and a real summer treat is the cucumber gazpacho ramen ($22), served cold.
    — Anne Ewbank, Sacbee.com, 19 Aug. 2026
Definition of subterranean
Noun
  • As her anger and resistance grow, her body begins to transform into porcelain, becoming a powerful symbol of her silent rebellion and her fight to reclaim her own identity.
    — Leo Barraclough, Variety, 25 Aug. 2026
  • The stock also cleared minor resistance from late July near $71, which now becomes initial support.
    — Katie Stockton, CNBC, 24 Aug. 2026
Definition of resistance
Adverb
  • From there, the group could stealthily disperse the new strain through air-handling systems at major livestock farms across the United States.
    — Elizabeth Sherwood-Randall, Foreign Affairs, 18 Aug. 2026
  • World Liberty is celebrating the major milestone, while critics worry this is a new wrinkle on the classic case of the fox guarding the henhouse that will give corporations and foreign actors a new way to stealthily curry favor with the White House.
    — Matt Egan, CNN Money, 17 Aug. 2026
Definition of stealthily
Adjective
  • By mid-July, an undercover FBI informant posing as an ISIS facilitator was messaging with her.
    — Lila Dominus, CNN Money, 20 Aug. 2026
  • An undercover officer posing as a UPS driver saw Vargas, 35, outside the building where the packages were being shipped, prosecutors said.
    — Alexa Herrera, CBS News, 19 Aug. 2026
Definition of undercover
Adverb
  • Right now, there are no indications exploits are being used to install anything other than Monero miners, which surreptitiously harness a Mac’s resources to perform mathematical operations that generate the cryptocurrency for the attacker.
    — Dan Goodin, ArsTechnica, 14 Aug. 2026
  • That's not the first time a president surreptitiously switched planes.
    — Phaedra Trethan, USA Today, 11 Aug. 2026
Definition of surreptitiously
Adjective
  • Bannerman centers on the eponymous Paul Bannerman, a lethal covert operative who convinces a group of the world’s most deadly assassins to quit the spy game for a chance to lead normal lives in the suburbs of Connecticut.
    — Nellie Andreeva, Deadline, 20 Aug. 2026
  • In Asia, there is no present analog to the major shocks of the 1970s, which drove Seoul and Taipei to pursue covert nuclear programs.
    — Kurt M. Campbell, Foreign Affairs, 18 Aug. 2026
Definition of covert
Adverb
  • Because Iran is a theocratic dictatorship that routinely arrests and in some cases executes journalists, Western reporters hoping to cover the country must either work clandestinely or submit to government supervision.
    — James Kirchick, The Atlantic, 29 July 2026
  • Soon afterward, social media commenters were speculating about whether Sierra broke into the office or was caught clandestinely shredding documents.
    — Don Stacom, Hartford Courant, 10 July 2026
Definition of clandestinely

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Cite this Entry

“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 26 Aug. 2026.

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More from Merriam-Webster on underground

Britannica.com: Encyclopedia article about underground

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