noun |
adj |
verb |
adv |
(adj) secret, undercover, surreptitious, hole-and-corner, hugger-mugger, hush-hush, clandestine, cloak-and-dagger
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
(adj) belowground
under the level of the ground
belowground storage areas; underground caverns
(noun) metro, tube, subway, subway system
an electric railway operating below the surface of the ground (usually in a city)
in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'
(noun) resistance
a secret group organized to overthrow a government or occupation force