archfiend

1. (preceded by “the”, often capitalized) Satan.Examples: "So stretcht out huge in length the Arch-fiend lay Chain’d on the burning Lake,"; "In disobedience to his God, Did man himself call down the rod? Or did th’ arch-fiend, from Heav’n that fell, Inspire the mischief to rebel?"; "All, save I, were at rest or in enjoyment; I, like the arch fiend, bore a hell within me, and finding myself unsympathised with, wished to tear up the trees, spread havoc and destruction around me, and then to have sat down and enjoyed the ruin."Synonyms: Lucifercapitalizedoften

2. (transferred sense) A diabolically evil person.Examples: "1690, anonymous translator, The Royal Wanton (attributed to Gregorio Leti), London: F.B., Part 5, p. 48, […] her Arch-fiend and Devil of a Lord, had impudently sent the same Villain to abuse her once again."; "So this is a plot to shield this arch-fiend, and I have detected it. A word from me, and three heads besides his would roll from their shoulders!"; "Possibly Beauty Smith, arch-fiend and tormentor, was capable of breaking White Fang’s spirit, but as yet there were not signs of his succeeding."