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
Jim Cramer, CNBC, 28 May 2026
Mother senses that her children are imprisoned in an underground area and asks that they be set free.
—Dani Di Placido, Forbes.com, 28 May 2026
Rachel Monroe, New Yorker, 14 May 2026
The Warsaw Rising Museum illustrates the plight of the Polish underground and the 63-day-long resistance against the German occupation.
—Kasia Dietz, Travel + Leisure, 13 May 2026
Fangxing Fran Li, The Conversation, 27 May 2026
In many cases they were situated underground, or in areas expressly designed to isolate detainees.
—Amer Matar, The Dial, 26 May 2026
See All Example Sentences for underground
Adjective
Oppenheimer upgraded Quanta Services to buy from hold, pointing to exposure to power generation, underground delivery network modernization, and AI development.
—Jim Cramer, CNBC, 28 May 2026
Mother senses that her children are imprisoned in an underground area and asks that they be set free.
—Dani Di Placido, Forbes.com, 28 May 2026
Noun
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
The Warsaw Rising Museum illustrates the plight of the Polish underground and the 63-day-long resistance against the German occupation.
—Kasia Dietz, Travel + Leisure, 13 May 2026
Adverb
Entergy New Orleans, the city’s main electric utility, has an accelerated grid-hardening plan that aims to replace existing utility poles with more fortified poles to withstand higher winds and selectively move some lines underground in high-risk areas.
—Fangxing Fran Li, The Conversation, 27 May 2026
In many cases they were situated underground, or in areas expressly designed to isolate detainees.
—Amer Matar, The Dial, 26 May 2026
See All Example Sentences for underground
Recent Examples of Synonyms for underground
Adjective
-
But in the current political climate, clandestine behaviors could win out.—
Robin George Andrews,
Scientific American,
19 May 2026
-
These relations are not based on secrecy or clandestine arrangements.—
Emma Bussey,
FOXNews.com,
17 May 2026
Adjective
-
The house spans almost 5,400 square feet, plus an additional 2,200 square feet of finished subterranean space executed to the same standard as the rest of the house.—
Mark David,
Robb Report,
22 May 2026
-
These subterranean passageways are significant in Hawaiian culture, providing shelter for the ancient communities and and being places for ceremonies and burials.—
Kathleen Wong,
USA Today,
20 May 2026
Noun
-
The 50-bed facility to be built in one of Kenya’s largest air force bases was expected to be operational by Friday, but has faced massive resistance from opposition leaders, health workers, and civil society.—
Martin K.N Siele,
semafor.com,
29 May 2026
-
Today’s players are reminded of the labor battles their predecessors went through, and the resistance to any sort of salary limit is just as unyielding.—
Jim Alexander,
Oc Register,
29 May 2026
Adjective
-
Comeaux also said undercover officers would focus on drug enforcement.—
Matthew Ablon,
CBS News,
1 June 2026
-
The Washington Nationals are in full damage control after an undercover journalist with the O’Keefe Media Group caught now former Director of Community Relations Sean Hudson claiming to be religiously discriminating against Catholic starting pitcher Trevor Williams.—
Jon Root OutKick,
FOXNews.com,
30 May 2026
Adverb
-
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
-
Fukada stealthily shades in these subtleties of feeling into the story with exacting skill, creating a drama that touches on social issues but never feels issues-driven.—
Leslie Felperin,
HollywoodReporter,
13 May 2026
Adjective
-
That is why Armenia’s election has become the focal point of an increasingly aggressive Russian political interference and covert action campaign.—
Wesley Alexander Hill,
Forbes.com,
30 May 2026
-
So does her strategy of releasing information in covert drips, often not revealing facts until the reader has likely figured them out.—
Literary Hub,
Literary Hub,
28 May 2026
Adverb
-
Scammers can create an AI replica of someone’s voice using a short recording of their speech — often pulled from social media or an earlier scam call that was surreptitiously recorded.—
CNN.com Wire Service,
Mercury News,
29 May 2026
-
Brown raised Boyne’s bond, leading to his incarceration, after Boyne surreptitiously photographed a prosecution document in court and shared it with other sympathetic bloggers.—
Edmund H. Mahony,
Hartford Courant,
26 May 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 3 Jun. 2026.
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