I've always thought that professionalism, whilst subject to discretisation, can be broadly categorised as having the capacity to concentrate on the task at hand ONLY. Obviously the professional in question needs to remove personal, psychological, (etc.) problems from their capacity in order that it is free for the professional task and does not influence their decision making processes. Additionally, being very good at said task will allow you to critically evaluate your own performance, identify immediately any personal problems that inadvertantly appear in your subconscious and remove them. I suppose this is something addressed by Human Factors courses.
Ability to be self-critical whilst performing excellently and maintaining accurate situational awareness. Ability to be flexible to decided levels in pre-defined circumstances (adapt to changing surroundings in order to maintain control). Maintaining control.
There are bound to be loads of other things too so let's call this a starter for 10...?