Porgy's partner (4)
I believe the answer is:
bess
'porgy's partner' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bess that I've seen before include "Queen Elizabeth 1 (sl)" , "George Gershwin opera 'Porgy and . . . .'" , "Nickname for English queen" , "Our Good Queen" , "Operatic mate for Porgy" .)