How do you define "professional" photographer?

I'm just curious how everyone defines "professional photographer?" Or amateur photographer. Or Hobby photographer. Etc. I've been asked before and wasn't sure what to say. I don't get paid for the photos I take. However, I do take the quality and things like composition and lighting very seriously. I also consider myself much better than amateur. If I say its a hobby, ironically that turns off most people. Makes it hard to get clients and taken seriously. Does paying someone somehow make them a professional? Let me know what you all think! Looking for advice.