Well let’s define the word professional:


Professional: One who is following an occupation as a means of livelihood or for gain.


For defining a professional poker player, I like to use the theory by Abraham Maslow: Maslow’s Hierarchy of Needs as a starting point. This theory is often depicted as a pyramid. If one can fulfill at least the bottom two levels by playing poker than one is considered a professional poker player.
For example the second level from the bottom is entitled “Safety” which would include shelter or housing. Without meeting these basic levels of “psychological needs” one cannot excel to the top of the pyramid. A professional poker player is a winning player they are synonymous. There are high and low swings and “bad runs” where a professional poker player may lose and there is no income figure that represents a professional poker player. However, in the long run a professional will win and has managed to protect himself or herself from going below the bottom two tiers of the pyramid. I also would like to add that a “Professional” is someone who while doing what they do, does not allow outside influences to hurt their performance. A professional is a student of their craft and eventually plays well enough to give back their knowledge without prejudice to others so that they can become professionals and excel in the craft that we call Poker.