<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>