beneath the surface of the earth; "water flowing underground"
in or into hiding or secret operation; "the organization was driven underground"
beneath the surface of the earth; "water flowing underground"
in or into hiding or secret operation; "the organization was driven underground"
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" पर्याय: clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush, secret, surreptitious, undercover,
under the level of the ground; "belowground storage areas"; "underground caverns" पर्याय: belowground,
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''" पर्याय: metro, tube, subway system, subway,
a secret group organized to overthrow a government or occupation force पर्याय: resistance,