Reduce rent (20% off, initially) (4)
I believe the answer is:
ease
'20 off initially' is the definition.
I can't judge whether this definition defines the answer.
'reduce rent' is the wordplay.
'reduce' means to remove the first letter (I've seen 'reduced' mean this).
'rent' becomes 'lease' (I've seen this before).
'lease' with its first letter taken away is 'EASE'.
(Other definitions for ease that I've seen before include "Poise or leisure" , "Rest and leisure" , "Freedom from pain or anxiety" , "Relief" , "Comfort and repose" .)