- underground
- underground [un′dər ground΄]adj.1. occurring, working, placed, used, etc. beneath the surface of the earth2. secret; hidden; undercover3. designating or of newspapers, films, music, etc. that are unconventional, experimental, radical, etc.adv.1. beneath the surface of the earth2. in or into secrecy or hiding; so as to be undercover; surreptitiouslyn.1. the entire region beneath the surface of the earth2. an underground space or passage3. a secret movement organized in a country to oppose or overthrow the government in power or enemy forces of occupation4. an underground movement in media, films, music, etc.5. Brit. a subway
English World dictionary. V. Neufeldt. 2014.