Rental contract (5)
I believe the answer is:
lease
'rental contract' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lease that I've seen before include "Rent -- easel (anag)" , "Contract for use of land or building" , "Rent (a property)" , "Contract allowing use of a property" , "Let (property)" .)