underground
名词 underground:
a secret group organized to overthrow a government or occupation force
同义词:resistance
an electric railway operating below the surface of the ground (usually in a city)
同义词:metro, tube, subway system, subway
形容词 underground:
under the level of the ground
同义词:belowground
conducted with or marked by hidden aims or methods
同义词:clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush, secret, surreptitious, undercover
副词 underground:
in or into hiding or secret operation
beneath the surface of the earth