underground[Anglais]

adjectif satellite
1 : under the level of the ground; "belowground storage areas"; "underground caverns"
2 : 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"
adverbe
1 : beneath the surface of the earth