Finally coppice thin wood (5)
I believe the answer is:
ebony
'wood' is the definition.
(I know that ebony is a type of wood)
'finally coppice thin' is the wordplay.
'finally' suggests the final letters.
'thin' becomes 'bony' (similar in meaning).
The last letter of 'coppice' is 'e'.
'e'+'bony'='EBONY'
(Other definitions for ebony that I've seen before include "Dark hardwood" , "'Hard, dark wood (5)'" , "hard stuff" , "Tree having black wood" , "Hard block tropical wood" .)