According to the dictionary, making it "big" is not a requirement of being a professional; you wouldn't even have to making your living to be a professional if you have the required skill or expertise: professional ( P ) Pronunciation Key (pr-fsh-nl) adj. Of, relating to, engaged in, or suitable for a profession: lawyers, doctors, and other professional people. Conforming to the standards of a profession: professional behavior. Engaging in a given activity as a source of livelihood or as a career: a professional writer. Performed by persons receiving pay: professional football. Having or showing great skill; expert: a professional repair job. n. A person following a profession, especially a learned profession. One who earns a living in a given or implied occupation: hired a professional to decorate the house. A skilled practitioner; an expert.