Definition

1. Noun:

   • A person motivated by irrational enthusiasm (as for a cause): A fanatic is someone who shows extreme, uncritical zeal or devotion, often to a point considered unreasonable by others.
   • A person with an obsessive interest in and enthusiasm for something: While often negative, it can also describe someone with an intense, all-consuming passion for a hobby or activity.

2. Adjective:

   • Marked by excessive enthusiasm for and intense devotion to a cause or idea: Describes behavior or beliefs characterized by extreme, often unreasoning, fervor. The variant "fanatical" is more commonly used in this adjectival form.

Examples of Usage

• Noun:

  • He was a religious fanatic who refused to tolerate other beliefs.
  • She's a fitness fanatic, working out for two hours every single day.

• Adjective:

  • His fanatic devotion to the political movement blinded him to its flaws.
  • They are fanatic about cleanliness, mopping the floors three times a day.

Advanced Usage

• The term often carries a negative connotation, implying that the enthusiasm is irrational, extreme, or potentially dangerous.
• It can be used in a more neutral or even mildly positive sense in informal contexts to describe great enthusiasm (e.g., "a crossword fanatic"), though "enthusiast" is often a more neutral alternative.

Variants and Related Words

• Fanatical (Adjective): The more frequent adjectival form of "fanatic."
  • She is a fanatical supporter of the team.
• Fanaticism (Noun): The quality of being fanatical; extreme, uncritical zeal.
  • The conflict was fueled by religious fanaticism.

Synonyms

• Zealot: A person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals.
• Enthusiast: A person who is highly interested in a particular activity or subject. (This is generally a more positive or neutral term.)
• Maniac: A person exhibiting extreme symptoms of wild behavior, especially violent aggression; or informally, a person with an extreme enthusiasm for something. (Stronger, more informal.)

Related Idioms and Phrases

• "Fanatic to the core": Completely and utterly fanatical.
  • He was a nationalist, fanatic to the core.
• The quote by Winston Churchill is a well-known characterization: "A fanatic is one who can't change his mind and won't change the subject."

Adjective

1. marked by excessive enthusiasm for and intense devotion to a cause or idea
   • rabid isolationist

Noun

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--Winston Churchill