Aristocrat's old coin (5)
I believe the answer is:
noble
I believe this is a double definition.
'aristocrat's' is the first definition.
(member of the nobility)
'old coin' is the second definition.
(I've seen this before)
(Other definitions for noble that I've seen before include "Of high rank or birth" , "fine" , "Illustrious - of high birth - old gold coin" , "Eminent" , "Grand, magnanimous" .)