Boon, benefit (5)
I believe the answer is:
asset
I believe this is a double definition.
'boon' is the first definition.
(I've seen this in another clue)
'benefit' is the second definition.
(I've seen this before)
(Other definitions for asset that I've seen before include "A thing of value" , "Something valuable to have" , "Item well worth having" , "Useful item" , "Item of property" .)