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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
Tarantula hawk wasps are a subtype of solitary insect that live in underground burrows. — Sean Donnelly, USA Today, 17 Sep. 2026 North Korea conducted six underground tests between 2006 and 2017 at the site at Mount Mantap in North Hamgyong province. — Katie Hunt, CNN Money, 17 Sep. 2026
Noun
To many, Anthony Bourdain is the patron saint of the culinary underground. — Patrick Ryan, USA Today, 13 Aug. 2026 The frustrations of manufacturing clean hydrogen have convinced many entrepreneurs and scientists to instead seek the element underground. — IEEE Spectrum, 11 Aug. 2026
Adverb
In 1998, the land in front of the MSI was redeveloped to move parking underground and replace the old surface lot with six acres of green space. — Adam Harrington, CBS News, 15 Sep. 2026 What competing on Food Network's Pitmasters taught him about cooking under pressure, from elaborate plating to burying food underground and cooking it over heated stones. — Sid Evans, Southern Living, 15 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
  • Across Greengrass’ three Bourne movies, the elite assassin turns against the clandestine institution that created him, determined to escape its grip and bring its covert operations to light.
    — Brian Davids, HollywoodReporter, 10 Sep. 2026
  • Or that the Apollo moon landing in 1969 was staged, the video shot on some clandestine movie set.
    — Susan Page, USA Today, 1 Sep. 2026
Definition of clandestine
Adjective
  • Comprising eight floors of retail, hospitality and art, Prada Galleria connects two sides of the central octagon in the landmark 19th-century location with a new subterranean passage.
    — Luisa Zargani, Footwear News, 15 Sep. 2026
  • An ingenious means of admitting natural light has been contrived so that, during the daytime, parts of these wonderfully austere and stony subterranean cellars, which ought to be very dark indeed, remain softly radiant.
    — Condé Nast, Condé Nast Traveler, 11 Sep. 2026
Definition of subterranean
Noun
  • The approach combines automotive-grade aluminum sheet with surface treatments designed to improve corrosion resistance and formability.
    — Neetika Walter, Interesting Engineering, 19 Sep. 2026
  • Delivery robots have been operating in Chicago through a pilot program, and the rollout has already faced resistance from some residents.
    — Kurt Knutsson, FOXNews.com, 19 Sep. 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
  • The growing fear in the community and rumors of undercover ICE agents in churches and church parking lots in other areas of the country has lead pastors to make major changes to their programming.
    — Lauren Costantino September 19, Miami Herald, 19 Sep. 2026
  • Murphy’s gang weren’t really outlaws to begin with — he was imprisoned for defending his daughter from some undercover cops, while Singh (Avi Nash) was arrested for his associations with socialism.
    — Katie Walsh, Los Angeles Times, 18 Sep. 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
  • Part thriller, part dark romantic comedy, Smokeshow centers on a covert operative, Rory (Fahy), who becomes entangled with her target, the charming and devastatingly earnest Nolan.
    — Matt Grobar, Deadline, 17 Sep. 2026
  • Regardless of their opinion about Denmark, Greenlanders are becoming aware of, and are unnerved by, this semi-covert, sometimes glaringly obvious American pressure.
    — Anne Applebaum, The Atlantic, 14 Sep. 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 23 Sep. 2026.

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More from Merriam-Webster on underground

Britannica.com: Encyclopedia article about underground

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