<p><strong>Adjective</strong></p><ul><li>following an occupation as a means of livelihood or for gain: a professional builder.</li><li>of, relating to, or connected with a profession: professional studies.</li><li>appropriate to a profession: professional objectivity.</li><li>engaged in one of the learned professions: A lawyer is a professional person.</li><li>following as a business an occupation ordinarily engaged in as a pastime: a professional golfer.</li><li>making a business or constant practice of something not properly to be regarded as a business: “A salesman,” he said, “is a professional optimist.”</li><li>undertaken or engaged in as a means of livelihood or for gain: professional baseball.</li><li>of or for a professional person or their place of business or work: a professional apartment; professional equipment.</li><li>done by an expert: professional car repairs.</li></ul><p><strong>Noun</strong></p><ul><li>a person who belongs to one of the professions, especially one of the learned professions.</li><li>a person who earns a living in a sport or other occupation frequently engaged in by amateurs: a golf professional.</li><li>an expert player, as of golf or tennis, serving as a teacher, consultant, performer, or contestant; pro.</li><li>a person who is expert at some kind of work: You can tell by her comments that this editor is a real professional.</li></ul>