Hagi said:
You might want to check the definition of professional:
"following an occupation as a means of livelihood or for gain: a professional builder. "
Professional is exactly a title you earn when you make money (AKA a livelihood) with something you do. Practice and skill only matter in so far as someone will hire you.
Working at a fast food restaurant does make you a professional cook. Cook is your profession. Therefore you're a professional cook. What it doesn't make you is a good cook.
If your friend isn't able to make a living out of being a pianist then she is NOT a professional pianist. She may be a very good pianist, but she isn't a professional pianist. Pianist is not her profession, thus she is not a professional pianist.
Rebecca Black is a professional artist. What she isn't is a good artist. But those are two very very different things. But you know, she's 13 so who cares whether she's good or not.
sigh...
Look at the Word professional.
notice, it is comprised of a word and a suffix.
Profession -al
now, as with most all words in the english language, adding '-al' as a suffix will mean 'of' or more accuratly 'pertaining to'
so Professional would litterally mean
Profession of.
and because it is an adj. it would be placed before a noun.
Professional Artist = Profession of someone that does art*
(the ist suffix denotes 'someone that (does)')
so now that we've properly disected 'Professional Artist'
lets look at it.
Profession of someone that does Art
now lets define the word 'Profession'
although there are multiple definitions, Most of which are tied to religion (profess- to announce/declare, ergo profession- is the act of announcement/declaring 'his profession of the end of days could be heard clear across the square')
Profession (when describing work)
a vocation(job) founded upon specialized skill and/or educational training
so a professional artist is:
someone of a job founded upon specialized skill and/or educational training for art.
-or-
someone with specialized/taught in making Art.
contrast to Professional builder:
some one specialized/taught in Building.
to Professional Killer:
some one specialized/taught in Killing.
You see a dictionary is ment to help you quickly understand the basic meaning behind a word so that you can understand them in the context they are probably used... from there you can then clarify the meaning through the context it is found in. As such, a Professional Criminal from your definition would be a person that is capable of making a living off of Crime. Yet in the context of the liturature it is found in, for instance Sherlock Holmes, it would mean a Criminal able to ply is trade and gain enough money off it to live comfortably with out getting caught... a feat of great skill.
Reading all this...
would you really still call Rebecca Black a Professional Artist?