1. following an occupation as a means of livelihood or for gain: a professional builder.
2. of, pertaining to, or connected with a profession: professional studies.
3. appropriate to a profession: professional objectivity.
4. engaged in one of the learned professions: A lawyer is a professional person.
5. following as a business an occupation ordinarily engaged in as a pastime: a professional golfer.
6. making a business or constant practice of something not properly to be regarded as a business: “A salesman,” he said, “is a professional optimist.”
7. undertaken or engaged in as a means of livelihood or for gain: professional baseball.
8. of or for a professional person or his or her place of business or work: a professional apartment; professional equipment.
9. done by a professional; expert: professional car repairs.
10. a person who belongs to one of the professions, esp. one of the learned professions.
11. a person who earns a living in a sport or other occupation frequently engaged in by amateurs: a golf professional.
12. an expert player, as of golf or tennis, serving as a teacher, consultant, performer, or contestant; pro.
13. a person who is expert at his or her work: You can tell by her comments that this editor is a real professional.
1740–50; profession + -al 1