underground

[ adverb, uhn-der-ground; adjective, noun, verb uhn-der-ground ]

/ adverb, ˈʌn dərˈgraʊnd; adjective, noun, verb ˈʌn dərˌgraʊnd /

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See synonyms for: underground / undergrounds on Thesaurus.com

adverb

beneath the surface of the ground: traveling underground by subway.

in concealment or secrecy; not openly: subversion carried on underground.

adjective

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

used, or for use, underground.

hidden or secret; not open: underground political activities.

published or produced by political or social radicals or nonconformists: an underground newspaper.

avant-garde; experimental: an underground movie.

critical of or attacking the established society or system: underground opinion.

of or for nonconformists; unusual: an underground vegetarian restaurant.

noun

the place or region beneath the surface of the ground.

an underground space or passage.

a secret organization fighting the established government or occupation forces: He fought in the French underground during the Nazi occupation of France.

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

Chiefly British. a subway system.

verb (used with object)

to place beneath the surface of the ground: to underground utility lines.

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Origin of underground

First recorded in 1565–75; under- + ground¹

Words nearby underground

undergird, underglaze, undergo, undergrad, undergraduate, underground, underground movie, underground railroad, underground trolley, undergrown, undergrowth

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use underground in a sentence

Italy may owe some of its seismic activity to carbon dioxide bubbling up from deep underground.
Carbon dioxide from Earth’s mantle may trigger some Italian earthquakes|Maria Temming|August 26, 2020|Science News
So the group of refuseniks — one of many underground cells plotting freedom — decided to hijack a plane.
The Failed Hijacking That Remade the Soviet Union|Eromo Egbejule|August 24, 2020|Ozy
Archaeologists had known since 1916 that some holes lurked underground.
Underground mega-monument found near Stonehenge|Avery Elizabeth Hurt|August 11, 2020|Science News For Students
Data from NASA’s Dawn orbiter, the study suggests, show signs that it may be harboring an ocean deep underground.
The dwarf planet Ceres might be home to an underground ocean of water|Neel Patel|August 11, 2020|MIT Technology Review

For example, the team found that a seismometer placed 380 meters underground near Auckland, New Zealand, was not only registering human activity, but saw that activity halved during the lockdowns.
COVID-19 lockdowns dramatically reduced seismic noise from humans|Carolyn Gramling|July 23, 2020|Science News
But underground classes have Persians getting with the beat.
Iran’s Becoming a Footloose Nation as Dance Lessons Spread|IranWire|January 2, 2015|DAILY BEAST
Atefeh says the participants in the underground classes she attends are mainly young women.
Iran’s Becoming a Footloose Nation as Dance Lessons Spread|IranWire|January 2, 2015|DAILY BEAST
Youssef said the jailings are not only driving the community underground but pushing many to move abroad.
Sisi Is Persecuting, Prosecuting, and Publicly Shaming Egypt’s Gays|Bel Trew|December 30, 2014|DAILY BEAST
“He literally went underground to hold services,” Moscow-based dissident and journalist Victor Davidoff said in an email.
Remembering the Russian Priest Who Fought the Orthodox Church|Cathy Young|December 28, 2014|DAILY BEAST
Unfortunately, the underground tunnels that were used to transport booze and, if necessary, escaping patrons, are off-limits.
The Bars That Made America Great|Nina Strochlic|December 28, 2014|DAILY BEAST
All over the world the just claims of organized labor are intermingled with the underground conspiracy of social revolution.
The Unsolved Riddle of Social Justice|Stephen Leacock
One thing was certain: Grandfather Mole could travel much faster through the water than he could underground.
The Tale of Grandfather Mole|Arthur Scott Bailey
And when he took an underground stroll he was almost sure to find a few angleworms, which furnished most of his meals.
The Tale of Grandfather Mole|Arthur Scott Bailey
When a besieged city suspects a mine, do not the inhabitants dig underground, and meet their enemy at his work?
The Pastor's Fire-side Vol. 3 of 4|Jane Porter
There was a look in his eyes almost as of one coming back from a long and dark journey underground into the light of day.
Bella Donna|Robert Hichens

British Dictionary definitions for underground

underground

adjective (ˈʌndəˌɡraʊnd)

occurring, situated, or used below ground levelan underground tunnel; an underground explosion

secret; hiddenunderground activities

adverb (ˌʌndəˈɡraʊnd)

going below ground levelthe tunnel led underground

into hiding or secrecythe group was driven underground

noun (ˈʌndəˌɡraʊnd)

a space or region below ground level

a movement dedicated to overthrowing a government or occupation forces, as in the European countries occupied by the German army in World War II
(as modifier)an underground group

the underground an electric passenger railway operated in underground tunnelsUS and Canadian equivalent: subway

(usually preceded by the)

any avant-garde, experimental, or subversive movement in popular art, films, music, etc
(as modifier)the underground press; underground music

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

underground

Origin of underground

Words nearby underground

Words related to underground

How to use underground in a sentence

British Dictionary definitions for underground