Synonyms for (noun) underground

Synonyms: metro, tube, underground, subway, subway system

Definition: an electric railway operating below the surface of the ground (usually in a city)

Usage: in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'

Similar words: railroad, railroad line, railway, railway line, railway system

Definition: line that is the commercial organization responsible for operating a system of transportation for trains that pull passengers or freight


Synonyms: resistance, underground

Definition: a secret group organized to overthrow a government or occupation force

Similar words: revolutionary group

Definition: a political unit organized to promote revolution

Synonyms for (adjective) underground

Synonyms: secret, undercover, underground, surreptitious, hole-and-corner, hugger-mugger, hush-hush, clandestine, cloak-and-dagger

Definition: conducted with or marked by hidden aims or methods

Usage: 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

Similar words: covert

Definition: secret or hidden; not openly practiced or engaged in or shown or avowed

Usage: covert actions by the CIA; covert funding for the rebels


Synonyms: underground, belowground

Definition: under the level of the ground

Usage: belowground storage areas; underground caverns

Similar words: subsurface

Definition: beneath the surface

Usage: subsurface materials of the moon