Giver; benefactor (5)
I believe the answer is:
donor
I believe this is a double definition.
'giver' is the first definition.
(I know that giver can be written as donor)
'benefactor' is the second definition.
(I know that donor is a type of benefactor)
(Other definitions for donor that I've seen before include "One who gives blood, for instance" , "Sponsor" , "One contributing" , "patron" , "Supporter" .)