definition of
demon

[1] #1 demon n. [devil, fiend, daemon, daimon] an evil supernatural being. wn

[2] #2 demon n. [monster, fiend, devil, ogre] a cruel wicked and inhuman person. wn

[3] #3 demon n. someone extremely diligent or skillful; "he worked like a demon to finish the job on time"; "she's a demon at math". wn