FANatic
WordNet
adjective
(1) Marked by excessive enthusiasm for and intense devotion to a cause or idea
"Rabid isolationist"
noun
(2) 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
WiktionaryText
Etymology
First attested in 1525. From from . Influenced by .
Adjective
- Fanatical.
- Showing evidence of possession by a god or demon; frenzied, over-zealous.
Noun
- A person who is zealously enthusiastic for some cause, especially in religion.
Quotations
- A zealot can't change his mind. A fanatic can't change his mind and won't change the subject. —Winston Churchill (attributed)
- A fanatic is one who redoubles his effort when he has forgotten his aim. —George Santayana