Party leader (5)
(Other definitions for rishi that I've seen before include "Hindu sage or saint" , "Spiritual leader" , "wise man" , "Guru" , "Poet" .)
'party leader?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hostess that I've seen before include "Person providing hospitality" , "Aircraft stewardess" , "She entertains guests" , "Mistress of ceremonies" , "Woman giving a party" .)