WordWeb Online

1. Marked by excessive enthusiasm for and intense devotion to a cause or idea
   "fanatic isolationist";
   - fanatical, overzealous, rabid

1. 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";
   - fiend

Derived forms: fanatics

See also: passionate

Type of: enthusiast, partisan, partizan

Encyclopedia: Fanatic