One can be a professional without being a member of a profession. The woman advertising for a professional had better say a professional what. She'll have lawyers come applying for the job of archbishop she wants filled.

And you don't have professional coal miners because you don't have amateur coal miners to distinguish them from.

"Hi, you probably don't recognize me because you're used to seeing me in my professional baseball player's uniform, but during the winter months I enjoy a good day's work breathing coal dust here two miles underground. When I get out and I'm looking for a good bar of soap I can't be bothered with dirty cash. I use American Excess. Don't leave home without it."