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
Robert A. Cronkleton, Kansas City Star, 12 June 2026
And that’s only the beginning—Santa Rosa is also home to seven natural swimming holes connected via underground caverns, including the 81-foot-deep Blue Hole, a favorite of scuba divers.
—Stacey Leasca, Travel + Leisure, 12 June 2026
Terry Gross, NPR, 18 May 2026
Though many people come to far West Texas for its isolation—the Unabomber’s slightly less reclusive brother did a stint here in the eighties, living at first in a crude underground shelter—Miller said that immigration-enforcement agents have been an intrusive presence for many years.
—Rachel Monroe, New Yorker, 14 May 2026
Noah Daly, Idaho Statesman, 11 June 2026
The president's comment may leave room for Iran to keep its enriched uranium that's buried underground.
—Mark Osborne, CBS News, 11 June 2026
See All Example Sentences for underground
Adjective
About two dozen people were treated after firefighters responded to reports of an unconscious person in the SubTropolis underground business complex in Kansas City’s Northland.
—Robert A. Cronkleton, Kansas City Star, 12 June 2026
And that’s only the beginning—Santa Rosa is also home to seven natural swimming holes connected via underground caverns, including the 81-foot-deep Blue Hole, a favorite of scuba divers.
—Stacey Leasca, Travel + Leisure, 12 June 2026
Noun
Zayd Ayers Dohrn spent much of his childhood underground and on the run.
—Terry Gross, NPR, 18 May 2026
Though many people come to far West Texas for its isolation—the Unabomber’s slightly less reclusive brother did a stint here in the eighties, living at first in a crude underground shelter—Miller said that immigration-enforcement agents have been an intrusive presence for many years.
—Rachel Monroe, New Yorker, 14 May 2026
Adverb
The first phase includes grading the site, building roadways around the property, constructing ball fields and relocating existing overhead power lines underground, the latter of which has already been completed in a contract with Idaho Power.
—Noah Daly, Idaho Statesman, 11 June 2026
The president's comment may leave room for Iran to keep its enriched uranium that's buried underground.
—Mark Osborne, CBS News, 11 June 2026
See All Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
-
Some may be announced publicly; others may happen in more clandestine ways.—
Eben Novy-Williams,
Sportico.com,
10 June 2026
-
But clandestine flows aren’t the biggest factor behind the market calm.—
Matt Egan,
CNN Money,
9 June 2026
Adjective
-
There’s an occasionally creepy aura in some subterranean places, but it’s wedged between sprawling vistas of a mountain range and a literal desert to traverse by motorcycle.—
Christopher Cruz,
Rolling Stone,
2 Dec. 2025
-
Bryan Robert Smith Photography The dig went on for five days, as investigators sifted through subterranean spaces and decades-old dirt.—
Richard Schlesinger,
CBS News,
25 Nov. 2025
Noun
-
Start sitting tall with your legs extended and a resistance band around your feet.—
RikkiLynn Shields Hannigan,
Health,
11 Dec. 2025
-
In response, two Afghan women wearing burqas to hide their identities post videos of themselves singing poetry as an act of resistance.—
Literary Hub,
Literary Hub,
11 Dec. 2025
Adverb
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The building is stealthily spacious with 40 bedrooms, and there’s a serious Sisley spa, designed with monkish minimalism, plus four superb restaurants.—
Matt Ortile,
Condé Nast Traveler,
3 June 2026
-
The strategic insights that matter most—how to respond to a competitive threat, whether an acquisition makes sense, how to restructure around AI, and which leadership gaps are stealthily costing the company—are only partly products of rigorous thinking.—
Julian Hayes II,
Forbes.com,
27 May 2026
Adjective
-
In 2005, an undercover investigator from the FDA called the farm and was told the milk was safe for human consumption.—
CNN Money,
CNN Money,
14 June 2026
-
Following a months-long undercover operation, in which a female officer posed as a romantic interest to extract information, Stagg was taken into custody, per The Guardian.—
Emily Blackwood,
PEOPLE,
13 June 2026
Adverb
-
Fox said the exchange between him and Wasser when he was called back to the restaurant took about 10-12 seconds, but defense attorney Karen Friedman Agnifilo suggested on Monday that the pair may have surreptitiously searched the backpack at that time and found the gun — or potentially planted it.—
Ben Brachfeld,
PEOPLE,
9 Dec. 2025
-
In a way, I am being surreptitiously employed by the owner for two minutes.—
Francesco Pacifico,
The Dial,
9 Dec. 2025
Adjective
-
Even the sweet, saintly Jimmy Carter, who cancelled a number of the agency’s more odious operations, signed a covert-action order to send weapons to resistance groups after the Soviet invasion of Afghanistan.—
Keith Gessen,
New Yorker,
16 July 2025
-
Also listed is Kojo Menne Asamoah, who is described as having knowledge of the Defendant’s use of covert tactics to promote the defamatory material.—
DeMicia Inman,
VIBE.com,
15 July 2025
Adverb
-
The audio recordings, shared by outlets including VSquare, Frontstory, Delfi Estonia, the Insider, and the Investigative Centre of Jan Kuciak, seem to have been clandestinely gathered.—
Timothy Nerozzi,
The Washington Examiner,
8 Apr. 2026
-
Many of them, like Lavrov, had to leave clandestinely because getting out with Russian permission is nearly impossible.—
Ivana Kottasová,
CNN Money,
22 Mar. 2026
Cite this Entry
“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 18 Jun. 2026.
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