Of a person or an animal: sly, stealthy.
Of a thing: done with evasive or guilty secrecy.
Of a thing: that has been acquired by theft; stolen; also (generally) taken stealthily.
Of a person, etc.: inclined to steal; pilfering, thieving.
Hidden, furtive, secretive.
Below the ground; below the surface of the Earth.
Outside the mainstream, especially unofficial and hidden from the authorities.
A movement or organisation of people who resist artistic convention.
A movement or organisation of people who resist political convention.
Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines).
Synonym of subway: a railway that is under the ground.
Below the ground.
Secretly.
To route electricity distribution cables underground.