infernal

nouns

an inhabitant of Hell
"his roar made the infernals quake"
is a type of (narrower)
someone who is no longer alive
"I wonder what the dead person would have done"

adjectives

characteristic of or resembling Hell
"infernal noise"; "infernal punishment"
is derived from
is derived from
pertains to
extremely evil or cruel; expressive of cruelty or befitting hell
"something demonic in him--something that could be cruel"; "fires lit up a diabolic scene"; "diabolical sorcerers under the influence of devils"; "a fiendish despot"; "hellish torture"; "infernal instruments of war"; "satanic cruelty"; "unholy grimaces"
expletives used informally as intensifiers
"he's a blasted idiot"; "it's a blamed shame"; "a blame cold winter"; "not a blessed dime"; "I'll be damned (or blessed or darned or goddamned) if I'll do any such thing"; "he's a damn (or goddam or goddamned) fool"; "a deuced idiot"; "an infernal nuisance"
of or pertaining to or characteristic of a very uncontrolled and intense fire
"infernal heat"
is derived from
pertains to
being of the underworld
"infernal regions"
antonym
is similar to
dwelling beneath the surface of the earth
"nether regions"
is similar to
of or relating to or characteristic of Hades or Tartarus
is similar to
hellish
"Hence loathed Melancholy.../In Stygian cave forlorn"- Milton
see also
morally bad or wrong
"evil purposes"; "an evil influence"; "evil deeds"