Philanthropist has name put in entrance (5)
I believe the answer is:
donor
'philanthropist' is the definition.
(thesaurus)
'name put in entrance' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'put in' is an insertion indicator.
'entrance' becomes 'door' (door is a kind of entrance).
'n' inserted into 'door' is 'DONOR'.
'has' is the link.
(Other definitions for donor that I've seen before include "One giving to a cause" , "Generous type" , "One who gives, perhaps blood" , "Maker of gift" , "One who gives, maybe blood" .)