Rent out or allow (3)
I believe the answer is:
let
This clue is a double definition.
'rent out' is the first definition.
(I've seen this in another clue)
'allow' is the second definition.
(I know that allow can be written as let)
(Other definitions for let that I've seen before include "Allow; rental period" , "Allow or lease" , "Award (a contract)" , "hired" , "Permit; lease" .)