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
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
Deborah Danan, Sun Sentinel, 26 June 2025
The Robust Nuclear Earth Penetrator, as the concept was known, would deliver a powerful shock to underground tunnels and bunkers.
—Geoff Brumfiel, NPR, 25 June 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
At Haifa’s Rambam Health Care Campus — home to the world’s largest underground fortified hospital — patients and staff relocated below ground to continue round-the-clock care.
—Deborah Danan, Sun Sentinel, 26 June 2025
The Robust Nuclear Earth Penetrator, as the concept was known, would deliver a powerful shock to underground tunnels and bunkers.
—Geoff Brumfiel, NPR, 25 June 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
-
American veterans and others have traveled to smaller, clandestine clinics for treatment to deal with depression, post-traumatic stress disorder and addiction.—
Eduardo Cuevas,
USA Today,
29 June 2025
-
Gi-hun, who’d found his way back in the clandestine gaming complex (situated inside a mountain on a remote island), is Player 456 again among a new round of contestants.—
Lorraine Ali,
Los Angeles Times,
28 June 2025
Adjective
-
For any subterranean tourist ready to explore the layers beneath the surface, this is where the adventure begins.—
Joseph V Micallef,
Forbes.com,
28 June 2025
-
In addition to precipitation, the Ayuk stream is also fed, in part, by subterranean streams.—
Lauren Liebhaber,
Miami Herald,
26 June 2025
Noun
-
Physical resistance is not required on the part of the victim to demonstrate lack of consent.—
Baltimore Sun staff,
Baltimore Sun,
7 July 2025
-
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
Adjective
-
Conan Edogawa and Detective Kogoro Mouri join the Nagano prefectural police to investigate a break-in at the observatory while uncovering a deeper plot involving undercover agents, betrayal, and vengeance.—
Naman Ramachandran,
Variety,
30 June 2025
-
On June 24, undercover agents attempted to purchase fireworks from Pan.—
Roni Jacobson,
New York Daily News,
30 June 2025
Adjective
-
Now, after Operation Midnight Hammer, arguably one of the most perfect covert military operations in U.S. history, who could argue? Even Trump’s most ardent critics had to give him credit.—
Sun Sentinel Editorial Board,
Sun Sentinel,
28 June 2025
-
This deliberately allusive narrative style enables the author to elude the topic of Nazism—or at least to hint at it in a covert way, thus making the novel acceptable to a wide German audience at the time of its publication in 1968.—
Ombline Damy,
JSTOR Daily,
26 June 2025
Adjective
-
The recent acquisition of 80% of its operating business by one of Europe’s oldest and most prestigious private equity firms, PAI Partners, values the brand at $3.6 billion.—
Katharina Kotrba,
Forbes.com,
30 June 2025
-
Robyn and John Horn of Little Rock have donated 105 works of art from their private collection to the Arkansas Museum of Fine Arts, the art center’s executive director announced Monday.—
Arkansas Online,
Arkansas Online,
30 June 2025
Cite this Entry
“Underground.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/underground. Accessed 13 Jul. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share