infernal in WordNet English dictionary

1. 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"
   blasted  blame  blamed  blessed  damn  damned  darned  deuced  goddam  goddamn  goddamned  infernal 
   
2. 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"
   demonic  diabolic  diabolical  fiendish  hellish  infernal  satanic  unholy 
   
3. being of the underworld
   "infernal regions"
   infernal 
   
4. characteristic of or resembling Hell
   "infernal noise"; "infernal punishment"
   infernal 
   
5. of or pertaining to or characteristic of a very uncontrolled and intense fire
   "infernal heat"
   infernal 
   

1. an inhabitant of Hell
   "his roar made the infernals quake"
   infernal