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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Dissimilar Words

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
When cellular connectivity becomes unreliable inside buildings, tunnels or underground spaces, robots can establish a self-organizing mesh network to maintain links between field units and command teams. — Jijo Malayil, Interesting Engineering, 17 Aug. 2026 In the case of Acid Bath, the band’s mystique and more underground status may have also played a role sparking this interest. — Quentin Thane Singer, Forbes.com, 17 Aug. 2026
Noun
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 Taking the dance sensation out of New York's gay underground and on the road, the singer vogued her way around the world on her 1990 Blond Ambition Tour, which kicked off in Japan that April. — Cara Lynn Shultz, PEOPLE, 29 June 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
  • Introduce subterranean parking, a row of tall trees or buildings, or a week of overcast weather, and the energy-positive calculus unravels.
    — New Atlas, New Atlas, 16 Aug. 2026
  • The reservoir is renewed by subterranean streams flowing through Dwyka rock formations dated at around 280 million years old, meaning the water moves through layers that existed long before dinosaurs walked the earth.
    — Connie Etemadi, USA Today, 14 Aug. 2026
Definition of subterranean
Noun
  • The outbreak has gained momentum since it was declared on May 15, as weak health infrastructure, community resistance and instability hinder the effort to identify and respond to cases.
    — CNN Money, CNN Money, 17 Aug. 2026
  • By way of thanks, the Swiss Football Association donated professional training equipment to the school, including Olympic lifting platforms, squat racks, medicine balls, resistance bands, agility hurdles and plyometric boxes.
    — Karen Billing, San Diego Union-Tribune, 17 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

Browse Nearby Words

undergraduates
underground
undergrounds
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Cite this Entry

“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 24 Aug. 2026.

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More from Merriam-Webster on underground

Nglish: Translation of underground for Spanish Speakers

Britannica.com: Encyclopedia article about underground

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