underground

adj. subterranean, below the surface of the ground; to be used below the surface of the ground; clandestine, conspiratorial

n. region beneath the ground's surface; secret organization fighting occupational forces or an established government; (British) subway, underground train system; subterranean passage

adv. not openly, in a clandestine manner; below the surface of the ground

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Noun
1. a secret group organized to overthrow a government or occupation force
(synonym) resistance
(hypernym) revolutionary group
(hyponym) Maquis
2. electric underground railway
(synonym) metro, subway, tube
(hypernym) railway, railroad, railroad line, railway line, railway system

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Adjective
1. under the level of the ground; "belowground storage areas"; "underground caverns"
(synonym) belowground
(similar) subsurface
2. conducted with or marked by hidden aims or methods; "clandestine intelligence operations"; "cloak-and-dagger activities behind enemy lines"; "hole-and-corner intrigue"; "secret missions"; "a secret agent"; "secret sales of arms"; "surreptitious mobilization of troops"; "an undercover investigation"; "underground resistance"
(synonym) clandestine, cloak-and-dagger, hole-and-corner(a), hugger-mugger, hush-hush, on the quiet(p), secret, surreptitious, undercover
(similar) covert
3. used of independent armed resistance forces; "guerrilla warfare"; "partisan forces"
(synonym) guerrilla(a), guerilla(a), irregular
(similar) partisan, partizan

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Adverb
1. in or into hiding or secret operation; "the organization was driven underground"
2. beneath the surface of the earth; "water flowing underground"

adj. underground, subterranean, below the surface of the ground

nm. underground, region beneath the ground's surface, secret organization fighting occupational forces or an established government

nm. underground, subway