Five back cut for sellers (7)
I believe the answer is:
vendors
'sellers' is the definition.
(I know this)
'five back cut' is the wordplay.
'five' becomes 'V' (Roman numeral).
'back' becomes 'endorse' (back can mean to support or endorse).
'cut' means to remove the last letter.
'endorse' with its last letter taken away is 'endors'.
'v'+'endors'='VENDORS'
'for' acts as a link.
(Other definitions for vendors that I've seen before include "They sell in Latin" , "Salesmen" , "Property sellers" , "they may be getting out of property" , "They sell things" .)