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English definition of “fiendish”

fiendish

adjective uk   /ˈfiːn.dɪʃ/ us  
evil and cruel: a fiendish attackUnkind, cruel and unfeelingViolent or aggressiveTreating people or animals badlyInsults and abuse clever and difficult, sometimes in a bad way: a fiendish crossword a fiendish plotComplicated and difficult to doDifficult to understand UK old-fashioned very great: a fiendish price I'm in a fiendish hurry.Serious and unpleasantNot attractive to look atInformal words for bad
fiendishness
noun [U] uk   /-nəs/ us  
Unkind, cruel and unfeelingViolent or aggressiveTreating people or animals badlyInsults and abuse
(Definition of fiendish from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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