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
These underground networks reflect Afghans’ hopes for a better future. — Mark Sappenfield, Christian Science Monitor, 9 Oct. 2026 Jerusalem — The strike plan called for hitting a vast underground complex in Gaza’s southern city of Rafah, comprised of dozens of rooms and a network of interconnecting tunnels. — Jeremy Diamond, CNN Money, 8 Oct. 2026
Noun
Since the late 1990s, taxpayers have been funding a program to stash extra Colorado River water underground, with the idea that it could be used as a backup in times of shortage. — Alex Hager, NPR, 31 Aug. 2026 On Facebook, discussion groups foster the feeling of a countercultural underground. — Ruby Cramer, New Yorker, 31 Aug. 2026
Adverb
No one has yet stored a data center’s heat underground at that scale. — Moones Alamooti, The Conversation, 9 Oct. 2026 The infrastructure is buried underground, already doing its work for the citizens. — Doug Ross, Chicago Tribune, 8 Oct. 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
  • Bridgers’ tour restricts phones, so the reader’s account had to stand in for the clandestine photo that might otherwise have accompanied the sighting.
    — Jeff Ihaza, Rolling Stone, 6 Oct. 2026
  • The Soviet Union operated an extensive clandestine biological weapons program despite being a party to the Biological Weapons Convention.
    — Krutika Kuppalli, STAT, 6 Oct. 2026
Definition of clandestine
Adjective
  • Officials estimated up to 200 cars — many of them parked in subterranean garages — were damaged as a result.
    — Los Angeles Times, Los Angeles Times, 14 Oct. 2026
  • The atmosphere is dark and subterranean, a Batcave of wellness.
    — Condé Nast, Condé Nast Traveler, 10 Oct. 2026
Definition of subterranean
Noun
  • Slota’s stated contempt for law enforcement and support for armed resistance was on display before his arrest.
    — Hudson Crozier, The Washington Examiner, 9 Oct. 2026
  • Through their grief and persistence, the film explores memory, resistance and a wound left open by institutional neglect.
    — Anna Marie de la Fuente, Variety, 9 Oct. 2026
Definition of resistance
Adverb
  • There had been small tweaks season to season as the series traveled to different locations — all of them telegraphed in the start-of-production slate photos that stealthily revealed the new logo (including the Season 4 one).
    — Nellie Andreeva, Deadline, 13 Oct. 2026
  • The spread of the video was aided by clippers, accounts that post hundreds of clips in a single day and are paid by companies to stealthily link these viral moments to their platforms.
    — CT Jones, Rolling Stone, 11 Sep. 2026
Definition of stealthily
Adjective
  • The show revolved around Crockett and Tubbs, two undercover detectives infiltrating South Florida’s criminal underworld.
    — Matt Grobar, Deadline, 13 Oct. 2026
  • At its center is a youngish man named Bob Arctor, an undercover cop who starts using drugs in order to infiltrate a house full of addicts in Southern California.
    — Hilton Als, New Yorker, 12 Oct. 2026
Definition of undercover
Adverb
  • Among the most intriguing possibilities, Brouhard said, is that Gulf nations exporting oil are surreptitiously paying Iran fees in exchange for safe transit through the Strait of Hormuz – even as they’re secured by US military escorts.
    — David Goldman, CNN Money, 6 Oct. 2026
  • In the first image above, Wardle can be seen using a simple terminal command to surreptitiously send a prompt to the Meta endpoint.
    — Dan Goodin, ArsTechnica, 21 Sep. 2026
Definition of surreptitiously
Adjective
  • This year has seen several notable incidents involving both overt and covert threats to undersea infrastructure, including Iranian efforts to impose fees on operators of undersea cables running through the contested Strait of Hormuz.
    — Jeremy Hsu, ArsTechnica, 14 Oct. 2026
  • From hippies to covert racists, psychedelics to cult-like workshop leaders, this is a world where any difference is still scrutinized and looked down on.
    — Aramide Tinubu, Variety, 13 Oct. 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
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Cite this Entry

“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 18 Oct. 2026.

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More from Merriam-Webster on underground

Britannica.com: Encyclopedia article about underground

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