/'ʌndəwɜ:ld; `ʌndɚ,wɝld/
n the underworld [sing]
1 (in mythology) place under the earth inhabited by the departed spirits of the dead （神话中的）阴间, 阴曹.
2 part of society that lives by vice and crime 下流社会; 黑社会
*police contacts in the London underworld伦敦黑社会中的警方眼线
* [attrib 作定语] leading underworld figures, ie notorious criminals 黑社会的头面人物（劣迹昭彰的罪犯）.

n [singular]
the criminals in a particular place and the criminal activities they are involved in
　New York's criminal underworld
the Underworld
the place where the spirits of the dead are believed to live, for example in ancient Greek stories