He was known for loving capital; nothing more (5)
I believe the answer is:
romeo
'he was known for loving' is the definition.
(I've seen this before)
'capital nothing more' is the wordplay.
'capital' becomes 'rome' (capital of Italy).
'nothing more' becomes 'O' (resembles 0).
'rome'+'o'='ROMEO'
(Other definitions for romeo that I've seen before include "Code word for the letter R" , "Star-crossed lover" , "He's on the lookout for it?" , "Dashing lover" , "Juliet's swain" .)