FIEND

devil, fiend, demon, daemon, daimon

(noun) an evil supernatural being

fanatic, fiend

(noun) a person motivated by irrational enthusiasm (as for a cause); “A fanatic is one who can’t change his mind and won’t change the subject”--Winston Churchill

monster, fiend, devil, demon, ogre

(noun) a cruel wicked and inhuman person

Source: WordNet® 3.1

Etymology

Noun

fiend (plural fiends)

A devil or demon; a malignant or diabolical being; an evil spirit.

Synonym: monster

A very evil person.

Synonym: monster

(obsolete) An enemy; a foe.

(religious, archaic) The enemy of mankind, specifically, the Devil; Satan.

(informal) An addict or fanatic.

Verb

fiend (third-person singular simple present fiends, present participle fiending, simple past and past participle fiended)

(slang, intransitive) To yearn; to be desperate (for something).

Anagrams

• endif, finde, fined, indef, indef.

Source: Wiktionary

Fiend, n. Etym: [OE. fend, find, fiend, feond, fiend, foe, AS. feónd; akin to OS. fiond, D. vijand enemy, OHG. fiant, G. feind, Icel. fjand, Sw. & Dan. fiende, Goth. fijands; orig. p.pr. of a verb meaning to hate, AS. feón, feógan, OHG. fi, Goth. fijan, Skr. piy to scorn; prob. akin to E. feud a quarrel. *81. Cf. Foe, Friend.]

Definition: An implacable or malicious foe; one who is diabolically wicked or cruel; an infernal being; -- applied specifically to the devil or a demon. Into this wild abyss the wary fiend Stood on the brink of Hell and looked a while. Milton. O woman! woman! when to ill thy mind Is bent, all hell contains no fouler fiend. Pope.

Source: Webster’s Unabridged Dictionary 1913 Edition