He may supply you, provisionally at least (6)
I believe the answer is:
grocer
'he may supply you provisionally at least' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is all the clue.
Can you help me to learn more?
(Other definitions for grocer that I've seen before include "Merchant who sells foodstuffs" , "Provisions purveyor" , "Food supplier" , "Chesterton's wicked tradesman" , "Provision merchant" .)