professional

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Of, relating to, engaged in, or suitable for a profession.
• adjective Conforming to the standards of a profession.
• adjective Engaging in a given activity as a source of livelihood or as a career.
• adjective Performed by persons receiving pay.
• adjective Having or showing great skill; expert.
• noun A person following a profession, especially a learned profession.
• noun One who earns a living in a given or implied occupation.
• noun A skilled practitioner; an expert.

from The Century Dictionary.

• Pertaining or appropriate to a profession or calling: as, professional studies; professional skill.
• Engaged in a profession; being such by profession.
• Undertaken or engaged in for money or as a means of subsistence: opposed to amateur: said of sports and amusements: as, a professional base-ball match; a professional performance of a play.
• noun One who regularly pursues any profession or art.
• noun Specifically, a person who makes his living by an art, game, or sport in which amateurs are accustomed to engage for amusement or recreation.

from the GNU version of the Collaborative International Dictionary of English.

• noun A person who prosecutes anything professionally, or for a livelihood, and not in the character of an amateur; a professional worker.
• adjective Of or pertaining to a profession, or calling; conforming to the rules or standards of a profession; following a profession
• adjective Engaged in by professionals; ; -- opposed to amateur.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A person who belongs to a profession
• noun A person who earns his living from a specified activity
• noun An expert.
• adjective Of, pertaining to, or in accordance with the (usually high) standards of a profession.
• adjective That is carried out for money, especially as a livelihood.
• adjective by extension Expert.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an authority qualified to teach apprentices
• adjective of or relating to or suitable as a profession
• noun an athlete who plays for pay
• adjective of or relating to a profession
• adjective engaged in a profession or engaging in as a profession or means of livelihood
• adjective characteristic of or befitting a profession or one engaged in a profession
• adjective engaged in by members of a profession
• noun a person engaged in one of the learned professions