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
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
Synonyms & Similar Words
Antonyms & Near Antonyms
Example Sentences
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Recent Examples of underground
Noah Haggerty, Los Angeles Times, 14 Feb. 2025
Who’s going to deal with that leaking underground storage tank releasing petroleum into the soil if the business owner can’t or won’t?
—Megan Schrader, The Denver Post, 7 Feb. 2025
Gordon G. Chang, Newsweek, 31 Oct. 2024
Fraudsters can access your personal details — such as your name and email address — and sell them on the criminal underground known as the dark web.
—Kate O'Flaherty, Forbes, 11 Sep. 2024
Charles Feigin / The Conversation, Popular Science, 23 Jan. 2025
While the therapeutic use of psychedelics has long happened underground, clinical research into psilocybin’s potential to treat ailments like major depression and post-traumatic stress disorder has fueled greater acceptance of it in the mainstream.
—Tiney Ricciardi, The Denver Post, 21 Jan. 2025
See all Example Sentences for underground 
Adjective
The water level in the labyrinth of underground pipes began to drop, creating a vacuum in the system.
—Noah Haggerty, Los Angeles Times, 14 Feb. 2025
Who’s going to deal with that leaking underground storage tank releasing petroleum into the soil if the business owner can’t or won’t?
—Megan Schrader, The Denver Post, 7 Feb. 2025
Noun
Hailing from Sacramento, X-Raided emerged as a leading figure in the early nineties underground rap scene.
—Gordon G. Chang, Newsweek, 31 Oct. 2024
Fraudsters can access your personal details — such as your name and email address — and sell them on the criminal underground known as the dark web.
—Kate O'Flaherty, Forbes, 11 Sep. 2024
Adverb
This probably happened because a clear image isn’t very important underground.
—Charles Feigin / The Conversation, Popular Science, 23 Jan. 2025
While the therapeutic use of psychedelics has long happened underground, clinical research into psilocybin’s potential to treat ailments like major depression and post-traumatic stress disorder has fueled greater acceptance of it in the mainstream.
—Tiney Ricciardi, The Denver Post, 21 Jan. 2025
See all Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
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Brendan Marks and Matt Baker uncovered documents that illustrate North Carolina’s clandestine research into conference realignment.—
Chris Branch,
The Athletic,
12 Feb. 2025
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This defiant and entertaining work playfully uses headshots and avatars to visualize clandestine audio recordings documenting years of Kafkaesque impositions, threats, and vital dissident art.—
Samantha Bergeson,
IndieWire,
10 Feb. 2025
Adjective
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The broken subterranean pipe is designed to provide pressurized water to the depot’s thousands of sprinkler heads in the event of a fire.—
Evan Simko-Bednarski,
New York Daily News,
15 Feb. 2025
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Off the coast of Japan, thousands of feet below the surface, the seafloor explodes with heat. Cracks and vents in the rocky sediment allow boiling seawater heated by subterranean magma to shoot back up into the sea, reaching temperatures of more than 700 degrees Fahrenheit.—
Irene Wright,
Miami Herald,
10 Feb. 2025
Noun
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The nearest resistance level is around $118, with another resistance zone at $123.—
Nishant Pant,
CNBC,
11 Feb. 2025
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Potential Drawbacks of Capping Credit Card Interest Rates The proposal has met resistance from financial institutions.—
Justin Gest,
Newsweek,
11 Feb. 2025
Adjective
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The series also highlighted how Illinois statutes provide a degree of protection to politicians. To prosecute their case, the feds brought charges against Madigan after extensive wiretapping and cooperation from two undercover moles, former 25th Ward Ald.—
Megan Crepeau,
Chicago Tribune,
16 Feb. 2025
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In May 2023, an undercover police officer went into the Schenectady deli and grocery where Alaidrus was working behind the counter.—
Muri Assunção,
New York Daily News,
13 Feb. 2025
Adjective
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Universal revealed character details for each of the film's leads, which can be read below: Academy Award® nominee Johansson plays skilled covert operations expert Zora Bennett, contracted to lead a skilledteam on a top-secret mission to secure the genetic material.—
Thomas G. Moukawsher,
Newsweek,
5 Feb. 2025
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Johansson plays covert operations expert Zora Bennett, who leads the top-secret mission.—
Samantha Bergeson,
IndieWire,
5 Feb. 2025
Adjective
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The top official of the Social Security Administration quit over the weekend after Elon Musk's Department of Government Efficiency sought access to sensitive records containing the private information of Americans, according to a source familiar with the dispute.—
Joey Garrison,
USA TODAY,
19 Feb. 2025
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In recent years, UC San Diego has invested considerable resources into bridging the gap between academia and private industry.—
Natallie Rocha,
San Diego Union-Tribune,
18 Feb. 2025
Thesaurus Entries Near underground
Cite this Entry
“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 21 Feb. 2025.
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