Translation

• underground
• subterranean
• covert

Synonyms

• 密, 心腹, 暗昧, 暧昧, 机密, 机要, 潜在, 神秘, 神秘兮兮, 私, 私房, 秘, 秘密, 秘闻, 绝密, 诡秘, 详密, 贼溜溜, 隐秘, 黑
• 不法, 伪, 暗, 私, 私自, 越轨, 野鸡, 非官方, 非法, 非法定, 黑

Examples

• 今天在地上，明天在地下。
  Today above ground tomorrow under.
• 我意识到这个可怕的地下室是唯一可以救我们命的地方。
  I realized then that this awful cellar was the only place that could save our lives.
• 二十世纪中以后，北京胡同的数量显著地下降，因为人们把它们拆毁以便
  Since the mid-20th century, the number of hutongs in Beijing has dropped dramatically as they are demolished to make way for new roads and buildings.