A capital ring for a famous lover (5)
I believe the answer is:
romeo
'a famous lover' is the definition.
(I've seen this in another clue)
'a capital ring' is the wordplay.
'a capital' becomes 'rome' (capital of Italy).
'ring' becomes 'O' (letter resembling a ring).
'rome'+'o'='ROMEO'
'for' is the link.
(Other definitions for romeo that I've seen before include "Loving youth" , "Literary lover" , "Lover of Juliet" , "Dashing lover" , "Juliet's immortal lover" .)