Agent, informally (3)
I believe the answer is:
rep
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">agent informally</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 rep that I've seen before include "Representative; fabric" , "agent" , "Material for curtains" , "Stuff" , "Salesperson" .)