adj.
1.under the level of the ground
2.conducted with or marked by hidden aims or methods
3.used of independent armed resistance forces underground adv.
1.in or into hiding or secret operation
2.beneath the surface of the earth underground n.
1.a secret group organized to overthrow a government or occupation force
2.electric underground railway
Idiom of the Day
let one's emotions show
to be emotional (where it is not appropriate)
The mayor let his emotions show when his plan for the new stadium was defeated by the city council.