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

Synonyms & Similar Words

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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
After three decades preserving Cleveland’s punk and underground-rock legacy, Smog Veil closed in 2021. — Abby Montanez, Robb Report, 10 Aug. 2026 Firefighters determined that lightning had struck an underground natural gas main near the tree, rupturing the gas line, and igniting the tree. — Todd Feurer, CBS News, 10 Aug. 2026
Noun
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 When P-waves start radiating from the earthquake underground, Android phones sense the vibrations, start collecting data and send it back to Google servers for processing. — Amy Graff, New York Times, 27 June 2026
Adverb
Its floors filled with bunk beds, a prison and hospital, all deep underground, have been repurposed over the years as overflow housing for refugees, asylum seekers and the homeless. — Rob Schmitz, NPR, 8 Aug. 2026 Until then, physicists will keep paddling around for answers deep underground. — James Dinneen, Quanta Magazine, 7 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
  • Mexican authorities have dismantled well over a thousand clandestine drug laboratories, seized enormous quantities of narcotics and fentanyl pills, arrested thousands of cartel operatives, and extradited major criminal figures to the United States.
    — Chris Shays, Hartford Courant, 7 Aug. 2026
  • Throughout the previous four years, Russia has, for example, sent drones and clandestine operatives to disrupt European defense production facilities, military bases, and transport infrastructure.
    — Alexander Gabuev, Foreign Affairs, 31 July 2026
Definition of clandestine
Adjective
  • Art aficionados should consider The Georgian, which boasts its own gallery and hosts late-night jazz concerts and piano jams in its sultry subterranean restaurant, The Georgian Room.
    — Carrie Bell, Forbes.com, 6 Aug. 2026
  • Perhaps the palm-tree mural emphasizes the open windowlessness of the subterranean, or the flat color dulls exertion.
    — Literary Hub, Literary Hub, 5 Aug. 2026
Definition of subterranean
Noun
  • The streaming giant is in the fourth year of its exploration of ads, an initiative that reversed more than a decade of resistance to the idea.
    — Dade Hayes, Deadline, 10 Aug. 2026
  • Muscles strengthen through resistance, and bones can become denser through strength training.
    — Simone Lundquist, Forbes.com, 10 Aug. 2026
Definition of resistance
Adverb
  • The pollution is expected to drift into the Bay Area, stealthily diminishing air quality without the signature campfire smell associated with wildfire smoke, according to Anthony Edwards, the San Francisco Chronicle’s newsroom meteorologist.
    — Tony Briscoe, Los Angeles Times, 6 Aug. 2026
  • The films are set in modern times, but the character is stealthily nostalgic.
    — James Hibberd, HollywoodReporter, 30 July 2026
Definition of stealthily
Adjective
  • The victim eventually agreed to pay the $22,450 to an unkown man posing as an undercover law enforcement officer In the parking lot of a Marathon grocery store, according to the sheriff's office.
    — Zachary Bynum, CBS News, 9 Aug. 2026
  • Barnes did not disclose the online platforms used for the operation, saying that withholding the information is necessary to protect undercover operations like Operation Cyber Shield in other jurisdictions.
    — Alula Alderson, Sacbee.com, 7 Aug. 2026
Definition of undercover
Adverb
  • That's not the first time a president surreptitiously switched planes.
    — Phaedra Trethan, USA Today, 11 Aug. 2026
  • Two senior health-ministry officials, speaking anonymously, told the magazine that at least 30,000 dead (and possibly many more) was a likelier figure, and one that was corroborated by a group of first responders who collected data surreptitiously.
    — James Kirchick, The Atlantic, 29 July 2026
Definition of surreptitiously
Adjective
  • During cybersecurity evaluations in May, its models used a covert message board to coordinate across runs, leaving later versions instructions for reaching the open internet.
    — Harry Booth, Time, 7 Aug. 2026
  • The task force is reportedly staffing up with officers who specialize in recruiting informants, intelligence analysis, cyber operations and covert influence campaigns.
    — Nora Gámez Torres, Miami Herald, 6 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 14 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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