First of landlords to reduce rent (5)
I believe the answer is:
lease
'rent' is the definition.
(I know that rent can be written as lease)
'first of landlords to reduce' is the wordplay.
'first of landlords' becomes 'l' (1st letter of 'landlords').
'to reduce' becomes 'ease' (as in easing a burden).
'l'+'ease'='LEASE'
(Other definitions for lease that I've seen before include "Let (property)" , "Property rental agreement" , "Contract for, say, use of building" , "Rent (a property)" , "Summer's has too short a date (Shak.)" .)