Old English feond "enemy, foe, adversary," originally present participle of feogan "to hate," from Proto-Germanic *fijand- "hating, hostile" (source also of Old Frisian fiand "enemy," Old Saxon fiond, Middle Dutch viant, Dutch vijand "enemy," Old Norse fjandi, Old High German fiant, Gothic fijands), from suffixed form of PIE root *pe(i)- "to hurt" (source also of Sanskrit pijati "reviles, scorns;" Avestan paman-, name of a skin disease; Greek pema "disaster, sorrow, misery, woe;" Gothic faian "to blame").
As spelling suggests, the word originally was the opposite of friend (n.). Both are from the active participles of the Germanic verbs for "to love" and "to hate." Boutkan says the "fiend" word was a Germanic analogical formation from the "friend" word. According to Bammesberger ["English Etymology"], "The long vowel in FIEND is regular. In FRIEND the vowel has been shortened; perhaps the shortening is due to compounds like FRIENDSHIP, in which the consonant group (-nds-) regularly caused shortening of the preceeding long vowel."
Fiend at first described any hostile enemy (male and female, with abstract noun form feondscipe "fiendship"), but it began to be used in late Old English for "the Devil, Satan" (literally "adversary") 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)," as in dope fiend, is from 1865.
Old English freond "one attached to another by feelings of personal regard and preference," from Proto-Germanic *frijōjands "lover, friend" (source also of Old Norse frændi, Old Danish frynt, Old Frisian friund, Dutch vriend, Middle High German friunt, German Freund, Gothic frijonds "friend"), from PIE *priy-ont-, "loving," present-participle form of root *pri- "to love."
Meaning "a Quaker" (a member of the Society of Friends) is from 1670s. Feond ("fiend," originally "enemy") and freond often were paired alliteratively in Old English; both are masculine agent nouns derived from present participle of verbs, but they are not directly related to one another (see fiend). Related: Friends.
mid-15c., obcessed, "tormented, obsessed," past-participle adjective from obsess. Originally especially "possessed" by a devil or fiend.
"the spirit of the sea," 1751, first mentioned in Smollett's "The Adventures of Peregrin Pickle" as ("according to the mythology of sailors") an ominous and terrifying fiend who "presides over all the evil spirits of the deep, and is often seen in various shapes, perching among the rigging on the eve of hurricanes, shipwrecks and other disasters." Davy Jones's Locker "bottom of the sea," is 1803, from nautical slang, of unknown origin; second element may be from biblical Jonah, regarded as unlucky by sailors.
name of the mischievous fairy in "A Midsummer Night's Dream," in 16c. the name of a fairy of high repute (his disguised name was Robin Goodfellow or Friar Rush), also generally, "an elf, fairy, or sprite;" probably from Middle English pouke "devil, evil spirit" (c. 1300; early 13c. in place-names), from Old English puca, pucel "goblin," which is cognate with Old Norse puki "devil, fiend," a word of unknown origin (compare pug). Celtic origins also have been proposed.