Professional, a fruitless term victim to context. Today the term is most commonly applied to experts who have extensive skill or knowhow.1 It even describes products designed specifically for these experts. 1 Despite common foolish assumptions of professional implying quality, prowess and knowledge, the term professional does not arise from a similar background. Even nowadays, the use of the term professional can imply something entirely different from the norm, all by simply changing the context.
Originally professional stemmed from the classical Latin root word profess-, which is the past participial stem of profitēri (a combination of Pro + Fiteri).2 Pro means to state openly, declare, avow, to lay claim to, to makes one's business and to practice while Fiteri means to acknowledge.2 The root of profiteri is pro; a prefix that indicates favour of a political party, idea, concept, et cetera 3 In late 2nd century post-classical Latin, professional started to make connections with religion, becoming synonymous with the act of taking vows of a specific religious order, or to declare faith in a religion.1 The Latin understanding of professiō also meant qualified employment, in other words, an occupation.4 A professional is a person that has acquired skill over years, and applied them to a way of life, as opposed to an odd job such a street vendor. In modern English, the prefix pro is also attached to words as an indication of priority in time or space, and especially projecting ahead.3 The Romans borrowed pro from the Greek term prodromos (pro + dromos), which literally means before + race course.5 Properly, the term means running ahead of, precursor, or forerunner.5 In the Greek era, a forerunner was a person that would run well ahead of everyone to reach a destination safely in advance and thus ensuring protection for the group following behind.5
From an etymological point of view, professional has ties with being in plain sight, free of lies and deceit. If we were to accept a Greek bias, the term professional then naturally lends itself to responsibility by putting others' safety before your own. Many professionals today exhibit these qualities. Professors vow to promote the truth and firefighters run fearlessly into a blaze to protect those that desperately need to get out. Even professional athletes commonly give back to the community via charity events. A certain level of respect and understanding is implied by the word professional. That's probably where professional conduct in the office takes root, disrespect is intolerable, and thus unprofessional.
Although disrespecting is totally acceptable when money is involved. Since the 1779 text Remembrancer Public Events used the term professional in the context of a hireable army, professional became attributed to income.1 That is why a prostitute is sometimes called a professional.1 In this context, professional implies a completely different meaning especially when contrasted with professional office behaviour.
Without context, using professional alone leaves us wondering, "professional what?". It doesn't mean anything on its own. We may have assumptions tied in with the word itself, but without any supplement we can never grasp what professional really means.
1 "professional, adj. and n.". OED Online. September 2012. Oxford University Press. http://www.oed.com/view/Entry/152053?redirectedFrom=professional (accessed November 18, 2012).
2 IAC. "Half-professed." Dictionary.com and Definitions of Words at Dictionary.com. http://dictionary.reference.com/browse/half-professed (accessed November 18, 2012).
3 IAC. "Pro-." Dictionary.com. http://dictionary.reference.com/browse/pro- (accessed November 18, 2012).
4 "professio." http://en.wiktionary.org. en.wiktionary.org/wiki/professio#Latin (accessed November 18, 2012).
5 Biblos. "4274. prodromos." Bible Suite. http://biblesuite.com/greek/4274.htm (accessed November 18, 2012).