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
Relevance
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
Synonyms & Similar Words
Antonyms & Near Antonyms
as in resistance
a secret organization in a conquered country fighting against enemy forces
joined the underground while still a teenager
Synonyms & Similar Words
as in undercover
Related Words
Dissimilar Words
Example Sentences
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Recent Examples of underground
Arricca Elin Sansone, Southern Living, 27 June 2025
Trump said the uranium was stored 30 stories underground and is now buried in granite, concrete and steel.
—Bart Jansen, USA Today, 26 June 2025
Pavel Polityuk, USA Today, 4 July 2025
Switching from turf grass to native plants not only reduces water usage but also improves groundwater recharge, which moves water from the surface into underground aquifers.
—Claire Marks, Austin American Statesman, 2 July 2025
Ron Estes, MSNBC Newsweek, 29 Mar. 2025
And that song is just this crazy underground hit with all those guys.
—Emily Palmer Heller, Vulture, 2 June 2025
See All Example Sentences for underground
Adjective
Drywood termites don’t make colonies underground but live in structural timbers or even furniture and handrails inside a home.
—Arricca Elin Sansone, Southern Living, 27 June 2025
Trump said the uranium was stored 30 stories underground and is now buried in granite, concrete and steel.
—Bart Jansen, USA Today, 26 June 2025
Noun
Families huddled in underground metro stations for shelter and acrid smoke hung over the city centre.
—Pavel Polityuk, USA Today, 4 July 2025
Switching from turf grass to native plants not only reduces water usage but also improves groundwater recharge, which moves water from the surface into underground aquifers.
—Claire Marks, Austin American Statesman, 2 July 2025
Adverb
By the end of the first season, Marie and her new friends discover a secret underground facility where students are being experimented upon in the hopes of developing a super virus that can kill supes.
—Ron Estes, MSNBC Newsweek, 29 Mar. 2025
And that song is just this crazy underground hit with all those guys.
—Emily Palmer Heller, Vulture, 2 June 2025
See All Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
-
After paying private equity tycoon Jack McGinley $52 million in a clandestine off-market deal for the Georgian-style spread, which was designed by architect Don Nulty and built in 2009 for 9-1-1: Lone Star actor Rob Lowe, Levine and Prinsloo have put the place back on the market for $65 million.—
Wendy Bowman,
Robb Report,
10 July 2025
-
Built to listen for clandestine nuclear bomb blasts, the globe-spanning system detects low-frequency acoustic-gravity waves.—
Deni Ellis Béchard,
Scientific American,
9 July 2025
Adjective
-
Clark Kent and Lois Lane (Phyllis Coates) arrive in a small town to report on the world’s deepest oil well, which is handy for the town because the well is home to subterranean creatures and Clark Kent is secretly Superman.—
Rory Doherty,
Vulture,
11 July 2025
-
The second smallest is a subterranean snail from Spain, Czaja said.—
Miami Herald,
Miami Herald,
11 July 2025
Noun
-
Even if bitcoin is running into resistance at the $100,000-$110,000 level, other bets in the crypto market have taken off, including the digital assets infrastructure providers, such as Coinbase, which rose by 40% in June, its best month since last November.—
Afshan Musani,
CNBC,
7 July 2025
-
This reduces side effects and lowers the risk of antibiotic resistance.—
Kurt Knutsson,
FOXNews.com,
7 July 2025
Adjective
-
Watch a sneak peek below, then read on for more: Go undercover and solve local mysteries with Christmas shop owner Emily Lane!—
Matt Webb Mitovich,
TVLine,
7 July 2025
-
The guy who was in charge of buying apparently used a fake persona; this was very undercover, this is all happening secretly.—
Peter Balonon-Rosen,
Vox,
4 July 2025
Adjective
-
And Aleesha spontaneously planted a kiss on Luke while celebrating their successful covert operation to get Karina’s laptop.—
Claire Franken,
TVLine,
10 July 2025
-
Further, nations set on developing nuclear weapons can be subject to covert operations or outright military attacks, which can slow them down considerably.—
Brendan Rascius
July 8,
Miami Herald,
8 July 2025
Adjective
-
But Bondi and Bongino had a contentious exchange the following day at the White House, according to a person familiar with the matter who spoke on condition of anonymity to discuss a private conversation.—
Eric Tucker,
Los Angeles Times,
12 July 2025
-
Ahead of Carroll’s announcement by Dagenham & Redbridge on Saturday, the east London club confirmed they had been bought by a consortium of prominent Qatari private investors.—
Colin Millar,
New York Times,
12 July 2025
Cite this Entry
“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 18 Jul. 2025.
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