definition of
fiend

[1] #1 fiend n. [monster, devil, demon, ogre] a cruel wicked and inhuman person. wn

[2] #2 fiend n. [devil, demon, daemon, daimon] an evil supernatural being. wn

[3] #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