underground

• back-channel
• backstage
• backstairs
• behind-the-scenes
• belowground
• cabal
• clandestine
• clandestinely
• classified
• closed-door
• collusively
• concealed
• confidential
• confidentially
• conspiracy
• conspiratorially
• covert
• covertly
• furtive
• furtively
• hidden
• hole-and-corner
• hugger-mugger
• hush-hush
• in camera
• intimately
• inwardly
• off-the-books
• off-the-record
• offscreen
• offstage
• private
• privately
• privy
• resistance
• restricted
• secret
• secreted
• secretively
• secretly
• sneak
• sneakily
• sneaking
• sneaky
• sotto voce
• stealth
• stealthily
• stealthy
• subsurface
• subterranean
• surreptitious
• surreptitiously
• top secret
• unadvertised
• undercover
• underhand
• underhanded
• underhandedly
• undisclosed
• unexposed

• aboveboard
• aboveground
• acknowledged
• avowed
• clear
• evident
• manifest
• obvious
• open
• openly
• overt
• patent
• plain
• public
• publicly
• straightforward
• surface
• unclassified
• unconcealed
• undisguised
• unrestricted

• noun
  1. An underground railway, especially for mass transit of people in urban areas.
  2. A train that runs on such an underground railway.
  3. A rapid transit system, regardless of the elevation of its right of way.
  4. An underground walkway, tunnel for pedestrians (called pedestrian underpass in US).
  5. An underground route for pipes, sewers, etc.
  6. Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines).
  7. (with definite article) A movement or organisation of people who resist political convention.
  8. (with definite article) A movement or organisation of people who resist artistic convention.
• verb
  1. To route electricity distribution cables underground.
• adjective
  1. Below the ground; below the surface of the Earth.
  2. Hidden, furtive, secretive.
  3. Outside the mainstream, especially unofficial and hidden from the authorities.
• adverb
  1. Below the ground.
  2. Secretly.

• They found ancient ruins hidden underground during the excavation.
• The subway runs deep underground beneath the city.
• He was part of an underground movement that opposed the regime.
• The cables were buried underground to prevent weather damage.
• She listens to a lot of underground music that's not played on mainstream radio.

back-channel

saboteurs

• Trojan horse
• collaborators
• collaborators of enemy
• defacers
• demolishers
• desecraters
• desecrators
• despoilers
• destroyers
• graffitists
• infiltrators
• ravagers
• ruiners
• subversives
• taggers
• underground
• vandals
• wasters
• wreckers

yawning

backstage

backstairs

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