underground

American  

[uhn-der-ground, uhn-der-ground] / ˈʌn dərˈgraʊnd, ˈʌn dərˌgraʊnd /

adverb

1. beneath the surface of the ground.

   traveling underground by subway.

2. in concealment or secrecy; not openly.

   subversion carried on underground.

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adjective

1. existing, situated, operating, or taking place beneath the surface of the ground.

2. used, or for use, underground.

3. hidden or secret; not open.

   underground political activities.

4. published or produced by political or social radicals or nonconformists.

   an underground newspaper.

5. avant-garde; experimental.

   an underground movie.

6. critical of or attacking the established society or system.

   underground opinion.

7. of or for nonconformists; unusual.

   an underground vegetarian restaurant.

noun

undergrounds plural

1. the place or region beneath the surface of the ground.

2. an underground space or passage.

3. a secret organization fighting the established government or occupation forces.

   He fought in the French underground during the Nazi occupation of France.

4. (often initial capital letter) a movement or group existing outside the establishment and usually reflecting unorthodox, avant-garde, or radical views.

5. Chiefly British. a subway system.

verb (used with object)

1. to place beneath the surface of the ground.

   to underground utility lines.

underground British  

adjective

1. occurring, situated, or used below ground level

   an underground tunnel

   an underground explosion

2. secret; hidden

   underground activities

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adverb

1. going below ground level

   the tunnel led underground

2. into hiding or secrecy

   the group was driven underground

noun

1. a space or region below ground level

2. 1. a movement dedicated to overthrowing a government or occupation forces, as in the European countries occupied by the German army in World War II

   2. ( as modifier )

      an underground group

3. US and Canadian equivalent: subway.  an electric passenger railway operated in underground tunnels

4. (usually preceded by the)

   1. any avant-garde, experimental, or subversive movement in popular art, films, music, etc

   2. ( as modifier )

      the underground press

      underground music

Other Word Forms

Noun Inflected Forms

• undergrounds
  plural

Etymology

Origin of underground

First recorded in 1565–75; under- + ground ¹

Example Sentences

See Examples For:

underground undergrounds

That information may ultimately reveal more about the communities that produced the images and the cultural importance these underground spaces held over thousands of years.

From Science Daily ● Jul. 28, 2026

He said there should be an emphasis on "preserving natural field which provides habitat for insects, bugs, moths and caterpillars that need to incubate underground there."

From BBC ● Jul. 28, 2026

"We would rather leave our valuable minerals underground than export them without processing them locally. The era of 'horse and rider' investment relationships is over."

From Barron's ● Jul. 26, 2026

The break left a giant sinkhole on Sunset Boulevard and sent about 17 million gallons of water into surrounding neighborhoods, shuttering businesses, and flooding homes and underground parking.

From Los Angeles Times ● Jul. 25, 2026

And excavated deep beneath the surface, where the soil allowed, were shell-proof underground shelters, or dugouts in places thirty or more feet deep, approached down wooden staircases.

From "The War to End All Wars: World War I" by Russell Freedman

Glasgow and Budapest opened their undergrounds in 1896, as did Paris in 1900, New York in 1904, and Buenos Aires in 1913.

From Textbooks ● Dec. 14, 2022

This semester, Athey is teaching a class on subcultures and undergrounds at USC’s Roski School of Art and Design.

From Los Angeles Times ● Aug. 25, 2017

Joining her in conversation is Luc Sante, a critic known for his journalistic exploration of urban undergrounds; his most recent book, “The Other Paris,” gives similar treatment to the City of Light.

From New York Times ● Jan. 21, 2016

But he remained a name known primarily to those whose knowledge of the city’s music was steeped in various undergrounds.

From Washington Post ● Jun. 23, 2015

"I'm never sure where these French undergrounds are going to land me."

From The Triflers by Bartlett, Frederick Orin

Related Words

• clandestine
• experimental
• hidden
• private