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definitions

fiend

[feend]
noun
  1. Satan; the devil.
  2. any evil spirit; demon.
  3. a diabolically cruel or wicked person.
  4. a person or thing that causes mischief or annoyance: Those children are little fiends.
  5. Informal. a person who is extremely addicted to some pernicious habit: an opium fiend.
  6. Informal. a person who is excessively interested in some game, sport, etc.; fan; buff: a bridge fiend.
  7. a person who is highly skilled or gifted in something: a fiend at languages.
verb (used without object)
  1. Also feen [feen] /fin/. Slang. to desire greatly: just another junkie fiending after his next hit; As soon as I finish a cigarette I'm fiending to light another.

Origin of fiend

before 900; Middle English feend, Old English fēond; cognate with German Feind, Old Norse fjandr, Gothic fijands foe, orig. present participle of fijan to hate
Related formsfiend·like, adjectiveun·der·fiend, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for fiending

fiend

noun
  1. an evil spirit; demon; devil
  2. a person who is extremely wicked, esp in being very cruel or brutal
  3. informal
    1. a person who is intensely interested in or fond of somethinga fresh-air fiend; he is a fiend for cards
    2. an addicta drug fiend
  4. (informal) a mischievous or spiteful person, esp a child
Derived Formsfiendlike, adjective

Word Origin for fiend

Old English fēond; related to Old Norse fjāndi enemy, Gothic fijands, Old High German fīant

Fiend

noun
  1. the Fiend the devil; Satan
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for fiending

fiend

n.

Old English feond "enemy, foe," originally present participle of feogan "to hate," from Proto-Germanic *fijæjan (cf. Old Frisian fiand "enemy," Old Saxon fiond, Middle Dutch viant, Dutch vijand "enemy," Old Norse fjandi, Old High German fiant, Gothic fijands), from PIE root *pe(i)- "to blame, revile" (cf. Gothic faian "to blame;" see passion).

As spelling suggests, it was originally the opposite of friend, but the word began to be used in Old English for "Satan" (as the "enemy of mankind"), which shifted its sense to "diabolical person" (early 13c.). The old sense of the word devolved to foe, then to the imported word enemy. For spelling with -ie- see field. Meaning "devotee (of whatever is indicated)," e.g. dope fiend, is from 1865.

Online Etymology Dictionary, © 2010 Douglas Harper