un·der·world/`ʌndəˏwɜld; ˈʌndəwɜːld/ n [singular 单数] 1 the criminals in a place and the activities they are involved in 〔某地的〕罪犯; 黑社会; 犯罪活动: the London underworld of the 1960s 20 世纪 60 年代的伦敦黑社会 2 the place where the spirits of the dead live in ancient Greek stories 〔古希腊神话中的〕阴间,地府