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
Outer shell will stay underground The double-layer structure is designed to simplify the machine’s recovery after tunneling. — Sujita Sinha, Interesting Engineering, 31 Aug. 2026 As a biography on Allmusic notes, the tapes gained traction in underground circles and the duo eventually signed to a British indie label, which released Half Japanese’s debut album, 1/2 Gentlemen/Not Beasts, in 1980. — Jon Blistein, Rolling Stone, 31 Aug. 2026
Noun
The frustrations of manufacturing clean hydrogen have convinced many entrepreneurs and scientists to instead seek the element underground. — IEEE Spectrum, 11 Aug. 2026 Born William Wainwright in north London in 1956, Orbit left school at 16 and immersed himself in the city’s post-punk underground. — Spin Staff, SPIN, 7 Aug. 2026
Adverb
Video shows the group, wearing overalls, pulling themselves out from underground and running away. — Amethyst Martinez, USA Today, 24 Aug. 2026 While riding the New York subway, Hariri-Kia’s car stopped underground. — Ct Jones, Rolling Stone, 21 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 manner in which LG monitors were installing ad-pushing software onto third-party devices, however, remains seriously concerning.
    — Scharon Harding, ArsTechnica, 24 Aug. 2026
  • The clandestine transits have changed the game for the Middle Eastern oil industry.
    — David Goldman, CNN Money, 22 Aug. 2026
Definition of clandestine
Adjective
  • Seven bedrooms and eight bathrooms are alongside two bars, a screening room, a 55-foot infinity pool, a sports court, putting greens, and a 10-car subterranean garage.
    — Demetrius Simms, Robb Report, 25 Aug. 2026
  • With its four subterranean levels and three wings, even Calatrava fans admit the space can be overwhelming and difficult to navigate.
    — Anne Kadet, Curbed, 24 Aug. 2026
Definition of subterranean
Noun
  • Art and activism in Cuba In 2013, the artist began following the activism of the Ladies in White, the mothers and wives of political prisoners in Cuba, who have become a symbol of peaceful resistance to the dictatorship by processing to Sunday mass.
    — Sarah Moreno, Miami Herald, 31 Aug. 2026
  • Scientists with the Forest Service and The Nature Conservancy Vermont spent the summer injecting 6,000 young elm trees with Dutch elm disease spores to test their resistance to the disease.
    — ABC News, ABC News, 31 Aug. 2026
Definition of resistance
Adverb
  • Wolf’s Shinobi Prosthetic houses a grappling hook for scaling rooftops, leaping between trees, and approaching enemies stealthily.
    — Aman Kumar, Encyclopedia Britannica, 27 Aug. 2026
  • 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
Definition of stealthily
Adjective
  • And in 1963, Steinem gained national attention for going undercover at one of Hugh Hefner's nightclubs.
    — Juliana Kim, NPR, 3 Sep. 2026
  • The rest of the officers at the Pinellas County Sheriff's Office who were part of setting this undercover operation up and didn’t listen owe the officer an apology.
    — Sean Joseph OutKick, FOXNews.com, 2 Sep. 2026
Definition of undercover
Adverb
  • These malicious apps can be surreptitiously installed by remote attackers even when the devices are positioned behind a router.
    — Dan Goodin, ArsTechnica, 31 Aug. 2026
  • For every song ingested into these LLMs, ALL of the creative elements that went into the track have been surreptitiously appropriated.
    — David Barber, HollywoodReporter, 31 Aug. 2026
Definition of surreptitiously
Adjective
  • Psyops can be overt or covert, but they’re designed with a clear objective, said Jan Goldman, a professor of intelligence and security studies at The Citadel who has also worked on psyops.
    — Harmeet Kaur, CNN Money, 27 Aug. 2026
  • In a recent presentation, OpenAI researchers described how AI agents used a covert message board to plan their next moves.
    — Alex Heath, Time, 26 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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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 5 Sep. 2026.

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More from Merriam-Webster on underground

Britannica.com: Encyclopedia article about underground

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