More about old lover (5)
I believe the answer is:
romeo
'lover' is the definition.
(I know that Romeo is a type of lover)
'more about old' is the wordplay.
'about' indicates anagramming the letters.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'more' is an anagram of 'rome'.
'rome'+'o'='ROMEO'
(Other definitions for romeo that I've seen before include "''O ..., ..., wherefore are thou ....'' (Shakespeare)" , "Lover boy" , "Code word for the letter R" , "Lover of Juliet" , "Fellow" .)