Definition: a person motivated by irrational enthusiasm (as for a cause)
Usage: A fanatic is one who can't change his mind and won't change the subject--Winston Churchill
Similar words: partisan, partizan, enthusiast
Definition: an ardent and enthusiastic supporter of some person or activity
Synonyms: overzealous, fanatic, fanatical, rabid
Definition: marked by excessive enthusiasm for and intense devotion to a cause or idea
Usage: rabid isolationist
Similar words: passionate
Definition: having or expressing strong emotions