Associate, collaborator (7)
I believe the answer is:
partner
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">associate</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(partner is a kind of associate)</span><br/ ><br/ >'<span class="explanation-format__original">collaborator</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for partner that I've seen before include "Colleague, bedfellow" , "One sharing home or business" , "Accomplice" , "Either member of a couple" , "Confederate" .)