Con's opposite (3)
I believe the answer is:
pro
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">con's opposite</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for pro that I've seen before include "Top player" , "Preposition meaning for, in favour of" , "Favouring the professional" , "Of argument, say, in favour of" , "hooker" .)