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
Matthew Martin, semafor.com, 23 Apr. 2026
Recently Park spoke to the Times about the hardest parts of writing his new memoir, the importance of Project Blowed and taking his underground rap mentality with him from the gutter to the stars.
—Deputy Entertainment, Los Angeles Times, 23 Apr. 2026
Virginia Chamlee, PEOPLE, 18 Apr. 2026
The same goes for the Pixies, one of the most influential bands ever from the American underground, inspiring Nirvana and all that followed — yet never nominated.
—Rob Sheffield, Rolling Stone, 15 Apr. 2026
Jacek Krywko, Scientific American, 23 Apr. 2026
Millions of bees have been living underground there.
—Ryan Brennan, Kansas City Star, 23 Apr. 2026
See All Example Sentences for underground
Adjective
The all-underground Gold Line is Dubai’s largest transport project to date and is scheduled to be completed by September 2032.
—Matthew Martin, semafor.com, 23 Apr. 2026
Recently Park spoke to the Times about the hardest parts of writing his new memoir, the importance of Project Blowed and taking his underground rap mentality with him from the gutter to the stars.
—Deputy Entertainment, Los Angeles Times, 23 Apr. 2026
Noun
More than 60 radio stations from Boston to Tulsa have banned the song, but through word of mouth and the FM underground, 'The Pill' is selling 15,000 copies a week.
—Virginia Chamlee, PEOPLE, 18 Apr. 2026
The same goes for the Pixies, one of the most influential bands ever from the American underground, inspiring Nirvana and all that followed — yet never nominated.
—Rob Sheffield, Rolling Stone, 15 Apr. 2026
Adverb
An earthquake starts deep underground when huge tectonic forces cause stress to build up along a fault line, a massive fracture in Earth’s crust where blocks of rock have shifted and moved past each other.
—Jacek Krywko, Scientific American, 23 Apr. 2026
Millions of bees have been living underground there.
—Ryan Brennan, Kansas City Star, 23 Apr. 2026
See All Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
-
The role of the two CIA agents who were returning from destroying a clandestine drug lab in the northern Mexican state of Chihuahua remains unclear.—
Los Angeles Times,
Los Angeles Times,
25 Apr. 2026
-
The role of the two CIA agents, who were returning from destroying a clandestine drug lab in the northern Mexican state of Chihuahua, remains unclear.—
CBS News,
CBS News,
25 Apr. 2026
Adjective
-
Endangered amphibians in California include the desert slender salamander, a subterranean amphibian found in just two spots in Riverside County.—
Sarah Linn,
Sacbee.com,
22 Apr. 2026
-
Take 25 Hours, in Long Island City, for example, which is freighted with a depressing ambience that is equal parts chemistry lab and subterranean grotto.—
Vince Aletti,
New Yorker,
17 Apr. 2026
Noun
-
The stable Taurus Sun meets resistance from intense Pluto in Aquarius, pushing tension between daily responsibilities and bigger career demands.—
Tarot.com,
New York Daily News,
25 Apr. 2026
-
The potential schedule change could further complicate a public-private project that has encountered steady resistance since it was announced two years ago.—
Gayla Cawley,
Boston Herald,
24 Apr. 2026
Adjective
-
These were actually undercover police officers.—
Literary Hub,
Literary Hub,
27 Apr. 2026
-
Federal prosecutors in Alabama secured an 11-count indictment accusing the organization of paying millions of dollars to some of those undercover informants and hiding the real purpose of the payments from its donors.—
Josh Meyer,
USA Today,
25 Apr. 2026
Adverb
-
That meant the magma could easily, and stealthily, pry its way through the crust, rather than having to smash through solid rock.—
Robin George Andrews,
Scientific American,
23 Apr. 2026
-
As Adrian Van Young put it in the Southwest Review, the book’s draw is stealthily structural.—
Brittany Allen,
Literary Hub,
23 Apr. 2026
Adjective
-
Indeed, our research suggests AI chatbots could easily be used for covert advertising to manipulate their human users.—
Brian Jay Tang,
The Conversation,
24 Apr. 2026
-
In a series first, Captain Sig Hansen launches an unprecedented covert scouting mission, deploying an underwater drone into the unknown waters in a bold attempt to locate the rare strain of king crab before the rest of the fleet arrives.—
Tony Maglio,
HollywoodReporter,
23 Apr. 2026
Adverb
-
Rarely before has a name so perfectly captured the look and feel of an endeavor that has, almost surreptitiously, dug its way into a space where it’s not supposed to be.—
Carl Juste,
Miami Herald,
22 Apr. 2026
-
Katas wan't recording in the front seat, so Christine, seated beside the wives in the back, surreptitiously pulled out her phone to record Bateman.—
Ryan Coleman,
Entertainment Weekly,
8 Apr. 2026
Adjective
-
Get Ready: Katy Perry Has Released a Sneak Peek of Her New Song And the internet has receipts.—
Mehera Bonner,
Marie Claire,
15 Mar. 2017
Cite this Entry
“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 1 May. 2026.
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