un·der·ground
ˌən-dər-ˈgrau̇nd 
1
: beneath the surface of the earth
2
: in or into hiding or secret operation
1
: a subterranean space or channel
2
: an underground city railway system
3
a
: a movement or group organized in strict secrecy among citizens especially in an occupied country for maintaining communications, popular solidarity, and concerted resistive action pending liberation
b
: a clandestine conspiratorial organization set up for revolutionary or other disruptive purposes especially against a civil order
c
: an unofficial, unsanctioned, or illegal but informal movement or group
especially
: a usually avant-garde group or movement that functions outside the establishment
un·der·ground
ˈən-dər-ˌgrau̇nd
1
: being, growing, operating, or situated below the surface of the ground
2
: conducted by secret means
3
a
: existing outside the establishment
an underground literary reputation
b
: existing outside the purview of tax collectors or statisticians
the underground economy
4
a
: produced or published outside the establishment especially by the avant-garde
underground movies
underground newspapers
b
: of or relating to the avant-garde underground
an underground moviemaker
an underground theater
Synonyms
Examples of underground in a Sentence
Adverb
They had been living underground as fugitives.
Noun
I've ridden on the New York subway, the Paris Metro, and the London Underground.
joined the underground while still a teenager
Adjective
The drugs are supplied through an underground network.
She loves the city's underground music scene.
Recent Examples on the Web
Bill Desowitz, IndieWire, 8 Jan. 2025
This hardline approach stifles business and pushes legitimate financial activity underground, which undermines FATF’s stated goals of transparency and combating illicit finance.
—Susie Violet Ward, Forbes, 7 Jan. 2025
Sammy Roth, Los Angeles Times, 7 Jan. 2025
Here's your complete guide to the 2024 underground experience This 1840s home looks like a white Christmas wonderland.
—Gege Reed, The Courier-Journal, 25 Nov. 2024
Jennifer Leigh Parker, Forbes, 12 Jan. 2025
Headlining Rolling Loud California 2025 By Matthew Strauss As a member of New York’s underground hip-hop scene, Wolfacejoeyy has brought pride to the Staten Island scene with projects like 22Joeyy and Valentino.
—Nina Corcoran, Pitchfork, 10 Jan. 2025
See all Example Sentences for underground 
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Adverb
But all of these puzzle pieces eventually came together with the help of a central tunnel and steep stairs leading underground (inspired by the subway in Washington, D.C.).
—Bill Desowitz, IndieWire, 8 Jan. 2025
This hardline approach stifles business and pushes legitimate financial activity underground, which undermines FATF’s stated goals of transparency and combating illicit finance.
—Susie Violet Ward, Forbes, 7 Jan. 2025
Noun
And as surface temperatures rise, their cool underground burrows may become important refuges.
—Sammy Roth, Los Angeles Times, 7 Jan. 2025
Here's your complete guide to the 2024 underground experience This 1840s home looks like a white Christmas wonderland.
—Gege Reed, The Courier-Journal, 25 Nov. 2024
Adjective
Between the five culinary offerings, including an underground fondue cave called La Fromagerie, two bars, clay tennis courts, an Olympic-sized swimming pool, a nearly 6,000 square-foot indoor and outdoor spa, there is really no reason to leave the property.
—Jennifer Leigh Parker, Forbes, 12 Jan. 2025
Headlining Rolling Loud California 2025 By Matthew Strauss As a member of New York’s underground hip-hop scene, Wolfacejoeyy has brought pride to the Staten Island scene with projects like 22Joeyy and Valentino.
—Nina Corcoran, Pitchfork, 10 Jan. 2025
See all Example Sentences for underground
Dictionary Entries Near underground
Cite this Entry
“Underground.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underground. Accessed 22 Jan. 2025.
Copy CitationKids Definition
underground
1 of 3 adverb
un·der·ground
ˌən-dər-ˈgrau̇nd
1
: below the surface of the ground
an underground passage
2
: in or into hiding or secret operation
the political party went underground
underground
2 of 3 noun
un·der·ground
ˈən-dər-ˌgrau̇nd
1
: a space under the surface of the ground
especially
: subway sense 2
2
: a secret political group
especially
: an organized body working in secret to overthrow a government or an occupying power
underground
3 of 3 adjective
un·der·ground
ˈən-dər-ˌgrau̇nd
1
: being, growing, operating, or located below the surface of the ground
an underground stream
2
: conducted secretly
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