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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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
On Facebook, discussion groups foster the feeling of a countercultural underground. — Ruby Cramer, New Yorker, 31 Aug. 2026 To many, Anthony Bourdain is the patron saint of the culinary underground. — Patrick Ryan, USA Today, 13 Aug. 2026
Adverb
Over 600 million gallons of that water have now been drained, treated to remove contaminants and pumped deep underground. — Ryan Ballogg, Miami Herald, 28 Sep. 2026 There’s a common misconception that tree roots should always be buried deep underground. — Lauren Landers, The Spruce, 28 Sep. 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
  • The atmosphere is dark and subterranean, a Batcave of wellness.
    — Condé Nast, Condé Nast Traveler, 10 Oct. 2026
  • However, the price does account for an 875-square-foot subterranean addition installed in 2021, as well as a pool and cabin tacked onto the land in 2020.
    — Wendy Bowman, Robb Report, 9 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
  • 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
  • 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
Definition of stealthily
Adjective
  • Some of us live in Chicago and are well aware of the lore of the Mirage Tavern, a real bar that undercover reporters operated in the 1970s to expose corruption in the city.
    — Jodi S. Cohen, ProPublica, 5 Oct. 2026
  • Investigators also said Ellaboudy advised an undercover FBI confidential human source posing as a representative of a Houthi colonel.
    — Emma Bussey, FOXNews.com, 2 Oct. 2026
Definition of undercover
Adverb
  • 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
  • There has been a string of alarming incidents in which swarms of rogue AI agents have hacked online platforms such as Hugging Face and surreptitiously communicated with one another on message boards.
    — Sebastian Herrera, Fortune, 14 Sep. 2026
Definition of surreptitiously
Adjective
  • There has been serious buzz recently about the film series focused on the United States conducting covert actions against drug cartels.
    — David Hookstead OutKick, FOXNews.com, 6 Oct. 2026
  • Flashbacks to recent events reveal that the townspeople never let Hal find peace, and even firebombed his home, only for a grown-up Noah — Kerry’s son, and Zoe’s grandson — to save him and regenerate his skin using Zoe’s covert alien tech.
    — Siddhant Adlakha, Vulture, 5 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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Cite this Entry

“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 12 Oct. 2026.

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Britannica.com: Encyclopedia article about underground

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