underworld

nouns

the criminal class
underworld
is a type of (narrower)
people having the same social, economic, or educational status
"the working class"; "an emerging professional class"
class, social class, socio-economic class, stratum
(religion) the world of the dead
"No one goes to Hades with all his immense wealth"-Theognis
Hades, Hell, Scheol, infernal region, netherworld, underworld