underground
adverb
• beneath the surface of the ground.
• "miners working underground"
Similar:
below ground,
below the surface,
under the earth,
in the earth,
underground
adjective
• situated beneath the surface of the ground.
• "an underground car park"
underground
noun
• an underground railway, especially the one in London.
• "travel chaos on the Underground"
• a group or movement organized secretly to work against an existing regime.
• "the French underground"
Similar:
resistance movement,
resistance,
illegal opposition,
partisans,
guerrillas,
freedom fighters,
Maquis,
• a group or movement seeking to explore alternative forms of lifestyle or artistic expression.
• "the late sixties underground"
underground
verb
• lay (cables) below ground level.
• "sections of electricity line had been undergrounded"
