fiend

Etymology

From Middle English feend, fēnd, fiend, feond, viend, veond (“enemy; demon”), from Old English fēond (“enemy”), from Proto-Germanic *fijandz. Compare Old Norse fjándi (Icelandic fjandi, Danish fjende, Norwegian fiende, Swedish fiende, West Frisian fijân, Low German Feend, Fiend, Dutch vijand, German Feind, Gothic 𐍆𐌹𐌾𐌰𐌽𐌳𐍃 (fijands)), with all of them meaning foe. The Old Norse and Gothic terms are present participles of the corresponding verbs fjá/𐍆𐌹𐌾𐌰𐌽 (fijan, “to hate”), from Proto-Indo-European *peh₁- (“to hate”) (compare Sanskrit पीयति (pī́yati, “(he) reviles”)).

noun

1. A devil or demon; a malignant or diabolical being; an evil spirit.
2. A very evil person.
3. (obsolete) An enemy; a foe.
   Religion teaches us to love everybody, be one fiend or friend.
4. (religious, archaic) The enemy of mankind, specifically, the Devil; Satan.
   At the confirmation ceremony the bishop would lay his hands on the child and tie around its forehead a linen band […]. This was believed to strengthen him against the assaults of the fiend […] 1971, Keith Thomas, Religion and the Decline of Magic, Folio Society, published 2012, page 35
5. (informal) An addict or fanatic.
   dope fiend
   He's been a jazz fiend since his teenage years.
   Now the sign of the Lamb is a modern daub, not that which hung like a "banner on the outward wall," when the celebrated "cigar-fiend" used to haunt the hostelrie consuming incredible quantities of the best Havanas. 1837-05-27, “The Poor Gentleman”, in New-York Mirror, volume 14, number 48, New York City: [G.P. Morris], →OCLC, page 377

verb

1. (slang, intransitive) To yearn; to be desperate (for something, especially drugs).
   I play it off, but I'm dreaming of you / And I'll try to keep my cool, but I'm fiendin' 1999, Macy Gray, Jeremy Ruzumna, Jinsoo Lim, David Wilder (lyrics and music), “I Try”
   I am back in San Francisco at the Clift Hotel, fiending for my fix. 2011, Emma J. Stephens, For a Dancer: The Memoir