Sentence examples for a fanatic from inspiring English sources

The phrase "a fanatic" is correct and usable in written English.
It can be used to describe someone who is extremely enthusiastic or devoted to a particular cause, belief, or activity, often to an excessive degree.
Example: "He is a fanatic when it comes to his favorite sports team, never missing a game and always wearing their colors."
Alternatives: "an enthusiast" or "a zealot."