Dealer or merchant (6)
I believe the answer is:
trader
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dealer</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that dealer can be written as Trader)</span><br/ ><br/ >'<span class="explanation-format__original">merchant</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that Trader is a type of merchant)</span><br/ ><br/ ></span>
(Other definitions for trader that I've seen before include "One buys and sells" , "Dealer, monger" , "Tarred the dealer badly" , "Person in the business of buying and selling" , "Red tar (anag)" .)