Pearl producer (6)
I believe the answer is:
oyster
'pearl producer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oyster that I've seen before include "Means to cross London" , "Pearl-bearing sea creature" , "Bivalve shellfish" , "Seafood item sometimes eaten alive" , "Pearl-producing bivalve" .)