#1 fiend n. [monster, devil, demon, ogre] a cruel wicked and inhuman person. wn
#2 fiend n. [devil, demon, daemon, daimon] an evil supernatural being. wn
#3 fiend n. [fanatic] 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. wn
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