noun.
An enemy; a foe.
noun.
Specifically, the enemy of mankind; Satan; the devil.
noun.
Hence, in a general sense, a devil; a demon; a malignant or diabolical being; an evil spirit.
noun.
An exceedingly wicked, cruel, spiteful, or destructive person: as, a dynamite fiend; a fire fiend.
noun.
A person who gives great annoyance; a persistent bore: as, the newspaper fiend; the hand-organ fiend.
noun.
Synonyms See devil.