For me, a "professional" photographer is a guy who takes orders, in one way or another. There are lots of other kinds of photographers, and I'm one of them. In fact, I wouldn't want to be a professional photographer -- for all but a few dozen people in the world, it's a tedious, uncreative, unreliable, low-paid job. A professional photographer is the guy who takes direction from the assistant principal at the grade school while shooting class photographs. So if you're taking direction from an assistant principal, just how high up the status/salary/job satisfaction pole could you be? A professional is a guy who shoots scenic photographs that will sell to people who will thumb-tack them above the couch, and offers them in 22 different sizes, and printed Wile-U-Wate.
Some other designations besides "amateur" (I would consider amateurs to be knowledgeable photographers who shoot for their own pleasure, at nobody else's direction except perhaps the wife and kids, which is far, far preferable to being a "professional") include such things as "artist" or "technician" or "journalist." A photographic artist is really looking for the soul of things, shoots at nobody's command, may or may not make a lot of money without changing his/her status as an artist, and often makes his/her primary economic living doing something else, such as working as a teacher. I would be much more interested in this person's ideas than in the ideas of a "professional." A journalist might be considered a specific subspecies of "professional," but I never heard a journalist call himself a "professional," although I have heard a guy referred to as a "real pro," which is different than "professional" photographer. A "real pro" is a guy who is willing and ready to stick his face into any kind of situation, and is used to designate all kinds of people wiling to do that -- reporters, soldiers, etc. I consider myself an odd kind of technician -- I'm not much interested in photography per se, but use it to support my painting habit -- I take pictures of little bits and piece of situations in which drawing is not appropriate, from which I create paintings. So, I don't want to be a professional photographer, and I never wanted to be one, and don't understand why people seem to chase after that designation. Artist or journalist would be okay, and technician is just fine. For me, wanting to be a "professional" that would be like wanting to be a professional postal clerk. Nothing against postal clerks (my father was one), but it just doesn't seem especially interesting in any way at all.