n. 1 a an evil spirit, a demon. b (prec. by the) the Devil. 2 a a very wicked or cruel person. b a person causing mischief or annoyance. 3 (with a qualifying word) sl. a devotee or addict (a fitness fiend). 4 something difficult or unpleasant. fiendish adj. fiendishly adv. fiendishness n. fiendlike adj.
[ OE feond f. Gmc ]