fanatic

If you’re apt to come off as a little zany and express extreme enthusiasm for a particular idea or thing, you may be described as a fanatic. "She’s a real vegetable fanatic; I’ve never seen someone so enthusiastic about gardening methods.

From the Latin fanaticus meaning “mad, enthusiastic,” the noun fanatic means “zealous person.” You know how right before the family gathers for Thanksgiving each year, everyone warns each other not to get your Uncle Jimmy started on the role of government in everyday life? That’s because he’s a fanatic, and as Winston Churchill so aptly phrased it, “A fanatic is someone who can’t change his mind and won’t change the subject.”

Definitions of fanatic
1

n 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”
Synonyms:
fiend
Type of:
enthusiast, partisan, partizan
an ardent and enthusiastic supporter of some person or activity

adj marked by excessive enthusiasm for and intense devotion to a cause or idea

Synonyms:
fanatical, overzealous, rabid
passionate
having or expressing strong emotions

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