infernal

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"