Cupcakes!
I think when I think 'artist', it's usually coupled with some form of melancholic personality; an artist's temperament so to speak. If I ever heard someone refer to themselves as an artist in ordinary conversation then I would feel the need to install tiny electric wipers in my eyes to clean off the pretentious splatter. Primarily because people generally tend to use the term as a sort of persona and badge of honor, rather than just calling themselves an illustrator, painter, potter, etc. But those particular terms don't sound romantic, inclusive and other-worldly enough. And we all know people want to be seen by others as 'different'.
Well, that's because it is a persona xD You can have your definition of it, but judging the definition of others' consideration of the term is also necessary, I would think, when dealing with the world of art.
For me personally, and I know a ton of people will disagree with me, but I wouldn't call myself a writer unless I was writing a lot. Constantly. Every day. I feel like being a writer is really easy, you just have to stop thinking about writing and actually write. But if you're not writing you're not a writer.
Sometimes I am a writer and sometimes I'm not; it's a fluid state. Right now I'll admit I probably am because I'm writing a couple thousand words a day. But there have been months where I haven't written at all (outside of things like forums) and I would not call myself a writer during those periods of time.