The word 'amateur,' as we know, is associated with someone who is unqualified or insufficiently skilled, and ultimately shows that a person is lacking. In relation to being artistic, the criteria that being an amateur suggests, that of enjoyment in and for the medium (and perhaps if successful conveying this enjoyment to the viewer), is marred if you demonstrate a lack of skill.
The measure of art, and being seen as an artist today, is therefore based on technical accomplishment. Whilst I value skill enormously, I do not believe that the acquirement of it should be at the expense of one's 'amateurish relationship' with the medium if you will. The word 'amateur' derives from the Latin amator, meaning ‘lover’, which in itself derives from the verb amare ‘to love’. So, perhaps a little too simply put, an amateur is someone who loves the activity they are engaged in.
Amare is in turn derived from the reconstructed Proto-Indo-European form am-a, am-, meaning ‘mother’ or ‘aunt’. When we look back at the indigenous cultures of Old Europe (7000 B.C. - 3000 B.C.), prior to the Indo-European (or Kurgan) invasions, their culture which in parts was assimilated by the Indo-Europeans, possessed an advanced aesthetic closely intertwined with the religion of the time. They were goddess worshipping, and their art was symbolic of their spirituality, which promoted the relatively peaceful, agrarian, and probably equalitarian social structures that existed then.
The etymological relationship between mother or aunt and love is thus not surprising, as not only was the transcendent female revered, but the mortal female also.
The etymology and historical meaning of the term ‘professional’ is from Middle English, meaning ‘pertaining or making entrance into a religious order’, with its first recorded occurrence being around 1420. Its usage was rare, and by 1747, the next recorded occurrence of the word, it takes on the more recognized meaning, ‘pertaining to, proper to, or connected with one's profession or calling’.
If we look at the root profes, where we get ‘profess’, we see that it comes from the Latin word 'profiteer', meaning to 'acknowledge, confirm, promise, or confess,' and was introduced into Middle English by way of the French. The past participle of this word is professes, which is how it came to us in English. The Latin word itself is composed of two parts, pro, generally meaning ‘towards,’ and fateor, meaning ‘to confess, admit, allow, reveal, or make known’. So to profess essentially conveys the admission of something, with the pro part emphasizing the revealing or outgoing nature of the act.