Meaning : A secret group organized to overthrow a government or occupation force.
Synonyms : resistance
Meaning : An electric railway operating below the surface of the ground (usually in a city).
Example :
In Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'.
Synonyms : metro, subway, subway system, tube
Meaning : In or into hiding or secret operation.
Example :
The organization was driven underground.
Meaning : Beneath the surface of the earth.
Example :
Water flowing underground.
Meaning : Under the level of the ground.
Example :
Belowground storage areas.
Underground caverns.
Synonyms : belowground
Meaning : Conducted with or marked by hidden aims or methods.
Example :
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.
Synonyms : clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush, secret, surreptitious, undercover