Webster took care of this for us, shithead.
Definition of professional
1 a :of, relating to, or characteristic of a profession
b :engaged in one of the learned professions
c (1) :characterized by or conforming to the technical or ethical standards of a profession (2) :exhibiting a courteous, conscientious, and generally businesslike manner in the workplace
2 a :participating for gain or livelihood in an activity or field of endeavor often engaged in by amateurs a professional golfer
b :having a particular profession as a permanent career a professional soldier
c :engaged in by persons receiving financial return professional football
3 :following a line of conduct as though it were a profession a professional patriot
— professionally adverb