a.

1. 地下的，地面下的
   An underground passage leads to the building across the street.

   一條地下通道通到街對面的大樓。

2. 祕密的，不公開的
   They were suspected of underground activities.

   他們被懷疑進行地下活動。

3. （電影，戲劇等）反主流的，先鋒派的

n.[C][theS]

1. 地面下層
2. （常大寫）【英】地下鐵
   I used to go to work by underground when I was in London.

   我在倫敦時，通常乘捷運上班。

3. （旨在反對現存政府等的）地下組織[G]
   He joined the underground to fight against the fascists.

   他參加了地下組織與法西斯作戰。

4. （常大寫）先鋒派團體[G]

ad.

1. 在地下
   Miners work underground.

   礦工在地下工作。

2. 祕密地，不公開地
   He went underground to avoid capture.

   他轉入祕密工作以免被捕。

adj.

adv.

1. beneath the surface of the ground.
2. in secrecy or hiding, especially as a result of carrying out subversive political activities.
3. seeking to explore alternative forms of lifestyle or artistic expression; radical and experimental.

n.

1. (often the Underground) Brit. an underground railway, especially the one in London.
2. a group or movement organized secretly to work against an existing regime.
3. a group or movement seeking to explore alternative forms of lifestyle or artistic expression.