ardent
Having very strong, eager, and passionate feelings about something.
Ardent means having intense enthusiasm or passion for something. An ardent reader doesn't just enjoy books: they devour them, think about them constantly, and can't wait to discuss their favorite stories. An ardent supporter of the school basketball team never misses a game and cheers with genuine excitement.
The word carries a sense of fire and heat. When you're ardent about something, your interest burns brightly. You might be an ardent collector of baseball cards, an ardent defender of your best friend, or an ardent believer in treating animals kindly.
Ardent feelings are strong and sincere, not casual or halfhearted. Someone might like pizza, but an ardent pizza lover talks about different styles, has strong opinions about toppings, and lights up when discussing their favorite pizza place.