Dealer, merchant (6)
I believe the answer is:
trader
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dealer</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">merchant</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(trader is a kind of merchant)</span><br/ ><br/ ></span>
(Other definitions for trader that I've seen before include "Red tar (anag)" , "Dealer who buys and sells" , "One buys and sells" , "Person in the business of buying and selling" , "One in business" .)