Entertainer of a multitude (4)
I believe the answer is:
host
This clue is a double definition.
'entertainer' is the first definition.
(host is a kind of entertainer)
'a multitude' is the second definition.
(host is a kind of multitude)
'of' is the link.
(Other definitions for host that I've seen before include "Myriad" , "Party giver" , "This man entertains" , "Compre" , "lot of people" .)