With a will, sample polished off (7)
I believe the answer is:
testate
'with a will' is the definition.
(I've seen this before)
'sample polished off' is the wordplay.
'sample' becomes 'test' (I've seen this before).
'polished off' becomes 'ate' (I've seen this in other clues).
'test'+'ate'='TESTATE'
(Other definitions for testate that I've seen before include "With a legally valid will" , "Having written a valid will" , "Leaving a will" , "Having made a valid will" , "Having made a will before death" .)