Grande ultimately thin in black (5)
I believe the answer is:
ebony
'black' is the definition.
(I know that ebony is a type of black)
'grande ultimately thin' is the wordplay.
'ultimately' says to take the final letters.
'thin' becomes 'bony' (similar in meaning).
The final letter of 'grande' is 'e'.
'e'+'bony'='EBONY'
'in' is the link.
(Other definitions for ebony that I've seen before include "Dark hardwood" , "Hard wood used for black piano keys and in cabinetwork" , "Hard dark-coloured wood" , "Wood - Boyne (anag)" , "Hard block tropical wood" .)