From Longman Dictionary of Contemporary Englishfiendfiend /fiːnd/ noun [countable] 1 BAD PERSONa very cruel, evil, or violent person a heartless fiend Both of them were fighting like fiends.a sex/rape fiend (=one who commits very unpleasant sex attacks)2 → television/sports/fresh-air etc fiend3 → drug/dope/cocaine etc fiend4 ROan evil spirit
Examples from the Corpus
fiend• Fiend turned inside out is still a fiend.• Father smiled from ear to ear, and he and I both ate like fiends.• These old people vote like fiends.• The architect must have been an opium fiend.• a sports fiendOrigin fiend Old English feond “enemy” 