Definition of "infernal"

infernal

/ɪnˈfɜː(ɹ)nəl/

adjective
comparative more infernal, superlative most infernal
1. Of or relating to hell, or the world of the dead; hellish.
2. (by extension) Of or relating to a fire or inferno.
3. Stygian, gloomy.
4. Diabolical or fiendish.
  Quotations
  Th' infernal Serpent; he it was, whose guileStird up with Envy and Revenge, deceiv'dThe Mother of Mankind
  1674, John Milton, Paradise Lost, Book I, lines 34–36
  the instruments or abettors in such infernal dealings
  1711 December 19 (Gregorian calendar), [Joseph Addison; Richard Steele et al.], “SATURDAY, December 8, 1711”, in The Spectator, number 244; republished in Alexander Chalmers, editor, The Spectator; a New Edition, […], volume III, New York, N.Y.: D[aniel] Appleton & Company, 1853
5. (as an expletive) Very annoying; damned.
  Quotations
  As I had to put up with the patronage and the lecturings, and the eyeglass of that infernal old woman, […]
  1905, Bram Stoker, The Man
  When are you ever going to learn to mind your own infernal business?
  1982, Sharon Green, The Warrior Within, page 10
noun
plural infernals
1. An inhabitant of the infernal regions, a demon.