Retailer who stirs sheep with poker (10)
I believe the answer is:
shopkeeper
'retailer' is the definition.
(I know that shopkeeper is a type of vendor)
'stirs sheep with poker' is the wordplay.
'stirs' indicates anagramming the letters.
'with' means one lot of letters go next to another.
'sheep' after 'poker' is 'pokersheep'.
'pokersheep' is an anagram of 'SHOPKEEPER'.
'who' is the link.
(Other definitions for shopkeeper that I've seen before include "E.g. newsagent" , "Counter-agent" , "Tradesperson" , "perhaps Napoleon's man in England?" .)