Porfessional vs Amateur

So what makes something worthy of being professional opposed to being amateur? 

Example: I am paid for my services as a set designer so that would make me a professional but I do not do that as my full time job, especially in this economy.  Since I do not do this full time to support myself I would be called a amateur. But wait I am being paid for my services.  In this case I would be called a professional amateur or a pro-am.  If I were to design sets full time and support myself I would considered professional even though I am turning in the same quality of work.  Now I have seen professionals , full time, do sloppy work either as an actor or a designer but are they a true professionals?  I know when I work on a project weather it's in a civic theatre, community theatre or a highly regarded award wining establishment I give 100% to the project trying to as 'professional' as I can.  I think the word professional has two meanings here #1 being paid for your work and #2 giving your best.  This is what the dictionary says about the word professional

1. 1. Of, relating to, engaged in, or suitable for a profession: lawyers, doctors, and other professional people.
   2. Conforming to the standards of a profession: professional behavior.
2. Engaging in a given activity as a source of livelihood or as a career: a professional writer.
3. Performed by persons receiving pay: professional football, set designer (I added that one in).
4. Having or showing great skill; expert: a professional repair job.

n.

1. A person following a profession, especially a learned profession.
2. One who earns a living in a given or implied occupation: hired a professional to decorate the house.
3. A skilled practitioner; an expert.

professionally pro·fes'sion·al·ly adv.

I would like to thank www.answers.com for the above information.  Tune in tomorrow for my thoughts of the word amateur.