Merchant who sells foodstuffs (6)
I believe the answer is:
grocer
'merchant who sells foodstuffs' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for grocer that I've seen before include "Retail merchant" , "Dealer in foodstuffs and household goods" , "Retailer of foodstuffs" , "Seller of household items and food" , "One supplying households" .)