Not professional (7)
I believe the answer is:
amateur
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not professional</span>' is the definition.<br/ ><span class="explanation-format__explanation">('amateur' is the opposite to 'professional')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for amateur that I've seen before include "One who pursues an activity as a pastime only" , "lacking professional expertise" , "he won't get paid" , "A non-professional sportsman" , "Inept, non-professional" .)