Underworld

Noun

 * 1) That part of society that is engaged in crime or vice.
 * 2)  The world of the dead, located underneath the world of the living; the afterlife.

Synonyms

 * netherworld

Thesaurus
Abaddon, Black Hand, Cosa Nostra, Dis, Gehenna, Hades, Hell, Naraka, Orcus, Pandemonium, Sheol, Tophet, abyss, avichi, bottomless pit, bowels, criminals, deep space, deeps, depths, gangdom, gangland, gaping depths, hades, hell, infernal pit, infernal regions, inferno, jahannan, limbo, lower world, nether world, netherworld, organized crime, outer space, perdition, place of torment, purgatory, shades below, the Mafia, the abyss, the bottomless pit, the grave, the mob, the pit, the rackets, the syndicate, the underworld, unfathomed deeps, unknown depths