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
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
Anna Kaufman, USA Today, 26 Sep. 2025
In 2020's Greenland, Gerard Butler's John Garrity, his estranged wife Allison (Morena Baccarin), and their young son Nathan (Roger Dale Floyd) narrowly escape an apocalyptic comet, finding shelter deep underground in a militarized doomsday bunker moments before impact.
—Mike Miller, Entertainment Weekly, 25 Sep. 2025
Vince Aletti, New Yorker, 3 Oct. 2025
According to an investigative report compiled by the Middle East Forum, using on-the-ground sources embedded in Iranian military installations across Syria since 2018, Iran has not only constructed underground tunnels and weapons depots for its disposal.
—Caitlin McFall, FOXNews.com, 3 Oct. 2025
Joseph Hernandez
august 20, Kansas City Star, 20 Aug. 2025
Millions of Americans own the rights to oil and gas underground.
—Jacob Orledge, ProPublica, 15 Aug. 2025
See All Example Sentences for underground
Adjective
She was sentenced to life in prison but escaped in November of 1979, living underground before being granted political asylum in Cuba in 1984.
—Anna Kaufman, USA Today, 26 Sep. 2025
In 2020's Greenland, Gerard Butler's John Garrity, his estranged wife Allison (Morena Baccarin), and their young son Nathan (Roger Dale Floyd) narrowly escape an apocalyptic comet, finding shelter deep underground in a militarized doomsday bunker moments before impact.
—Mike Miller, Entertainment Weekly, 25 Sep. 2025
Noun
Nervous, comic, plotless, and mesmerizing, his experimental shorts are classic underground cinema.
—Vince Aletti, New Yorker, 3 Oct. 2025
According to an investigative report compiled by the Middle East Forum, using on-the-ground sources embedded in Iranian military installations across Syria since 2018, Iran has not only constructed underground tunnels and weapons depots for its disposal.
—Caitlin McFall, FOXNews.com, 3 Oct. 2025
Adverb
Alternative rock band Goo Goo Dolls have been active in the music scene for nearly 40 years, getting their start in Buffalo, New York’s underground.
—Joseph Hernandez
august 20, Kansas City Star, 20 Aug. 2025
Millions of Americans own the rights to oil and gas underground.
—Jacob Orledge, ProPublica, 15 Aug. 2025
See All Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
-
There is a First World War U-boat that somehow glides from underneath Lake Michigan all the way to Croatia, commandeered by its captain, post-Armistice, for new and clandestine uses.—
Kathryn Schulz,
New Yorker,
22 Sep. 2025
-
Co-created by The New York Times bestselling author Carr and season 1 creator and showrunner David DiGilio, Dark Wolf follows Ben Edwards (Taylor Kitsch) on his journey from the SEALs to the clandestine side of CIA special operations.—
Susan Young,
PEOPLE,
11 Sep. 2025
Adjective
-
Unable to plausibly explain to the authorities what happened — or why she’s covered in her friends’ blood — Sarah is forced back to the subterranean depths to help locate her five missing companions.—
Caitlin White,
Variety,
3 Oct. 2025
-
While a few worlds in the Milky Way are believed to have liquid water hiding beneath a frozen surface, Enceladus isn't quite as secretive about its subterranean ocean.—
Eric Lagatta,
USA Today,
3 Oct. 2025
Noun
-
One more vote is needed to force a House vote over the resistance of Speaker Mike Johnson.—
Swapna Venugopal Ramaswamy,
USA Today,
4 Oct. 2025
-
Part of the town’s magic is in its remoteness and resistance to commercialization.—
Tara Massouleh McCay,
Southern Living,
4 Oct. 2025
Adjective
-
One person Smith communicated with was an undercover FBI agent, according to prosecutors.—
Julia Marnin,
Miami Herald,
30 Sep. 2025
-
Nearly 10 years after his demise, Holliday decides to go undercover as Powers to try and get a second chance with a struggling college team at South Georgia.—
Caroline Blair,
PEOPLE,
30 Sep. 2025
Adverb
-
Karalis supplies his colleagues with fluorescent orange utility uniforms and stealthily leads them through the back door of the Bank Al Muraqabah, located just below Rahim’s building.—
Peter Debruge,
Variety,
6 Sep. 2025
-
Others are stealthily looking for deals, sales, using layaway options and trading brand preferences for affordability.—
Leah Olajide,
Freep.com,
26 Aug. 2025
Adjective
-
This model protects against allergens like pollen and pet dander, smoke, dust, and does it all from a place of covert, inoffensive design.—
Julia Harrison,
Architectural Digest,
3 Oct. 2025
-
The detectives’ new case takes them to a remote Arctic research station, where a member of a covert British special forces mission has been shot dead.—
Jesse Whittock,
Deadline,
29 Sep. 2025
Adverb
-
Is he humiliated by being asked to leave surreptitiously for Olivia’s amusement, or is this a game for him too?—
Keith Phipps,
Vulture,
26 Sep. 2025
-
In many cases, fans were able to see that the tickets were surreptitiously forwarded to unrecognized accounts, presumably so they could be sold on third-party sites.—
Jacob Feldman,
Sportico.com,
24 Sep. 2025
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 8 Oct. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share