underground
[ˈʌndɚˌgraʊnd]
1
underground
adjective
- located or occurring below the surface of the earth
- secret and usually illegal
- of, relating to, or produced in a social and artistic world that is different and separate from the main part of society
2
underground
adverb
- below the surface of the earth
- in or into a place that is hidden or secret : out of the view of the public
3
underground
noun
- a system of trains that run below the ground in a large city : subway
- a group of people who secretly work to oppose or overthrow a government