Something to grease palm sugar, say? (9)
I believe the answer is:
sweetener
I believe this clue is a double definition.
'something to grease palm' is the first definition.
'sugar say?' is the second definition.
(sugar is a kind of sweetener)
(Other definitions for sweetener that I've seen before include "pill to replace sugar" , "carrot" , "Saccharin, for example" , "Bribe - sugar substitute" , "Extra inducement" .)