fanatic

A fanatic is someone who has a very strong opinion or enthusiasm for something, often to an extreme degree. This can lead them to behave strangely or intensely, usually without considering others' opinions.

When people talk about being fans of music, sports, or even politics, they're not necessarily fanatics. But when you hear that someone is a fanatic supporter of their favorite team, it means they'll do just about anything to see them win, and might even get aggressive if anyone disagrees with them. In everyday conversations, the word "fanatic" usually implies an unwavering dedication that's more than just enthusiasm – it's like being on a mission. For example, someone who only eats organic food all the time might be seen as a fanatic for their environmental views, but it could also be seen in people with very strong convictions about certain issues.