underground
Americanadverb
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beneath the surface of the ground.
traveling underground by subway.
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in concealment or secrecy; not openly.
subversion carried on underground.
adjective
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existing, situated, operating, or taking place beneath the surface of the ground.
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used, or for use, underground.
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hidden or secret; not open.
underground political activities.
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published or produced by political or social radicals or nonconformists.
an underground newspaper.
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avant-garde; experimental.
an underground movie.
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critical of or attacking the established society or system.
underground opinion.
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of or for nonconformists; unusual.
an underground vegetarian restaurant.
noun
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undergrounds
plural
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the place or region beneath the surface of the ground.
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an underground space or passage.
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a secret organization fighting the established government or occupation forces.
He fought in the French underground during the Nazi occupation of France.
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(often initial capital letter) a movement or group existing outside the establishment and usually reflecting unorthodox, avant-garde, or radical views.
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Chiefly British. a subway system.
verb (used with object)
adjective
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occurring, situated, or used below ground level
an underground tunnel
an underground explosion
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secret; hidden
underground activities
adverb
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going below ground level
the tunnel led underground
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into hiding or secrecy
the group was driven underground
noun
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a space or region below ground level
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a movement dedicated to overthrowing a government or occupation forces, as in the European countries occupied by the German army in World War II
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( as modifier )
an underground group
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US and Canadian equivalent: subway. an electric passenger railway operated in underground tunnels
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(usually preceded by the)
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any avant-garde, experimental, or subversive movement in popular art, films, music, etc
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( as modifier )
the underground press
underground music
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Other Word Forms
Noun Inflected Forms
Etymology
Origin of underground
Vocabulary lists containing underground
Florida's B.E.S.T. Common Prefixes: under-
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Spelling Practice, Unit 1
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Secret
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Gas in underground storage rose by 16 billion cubic feet last week to 3,169 Bcf, which was 185 Bcf above the five-year average and 28 Bcf below the year-earlier level.
From The Wall Street Journal ● Aug. 20, 2026
Closer to the crater rim, brighter streaks reveal fresher material that was excavated from greater depths underground.
From Science Daily ● Aug. 20, 2026
The result was something distinctly authentic with an underground quality that would have been hard to replicate at a sprawling, weeks-long festival.
From Los Angeles Times ● Aug. 18, 2026
One project the company has eyed up would involve boring tunnels for an underground freight-distribution system around airports and warehouses.
From BBC ● Aug. 18, 2026
They also maintained the underground route through which downed Allied plane crews reached the North Sea coast.
From "The Hiding Place" by Corrie ten Boom
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 Frederick Orin Bartlett
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
