Old Italian ruined manor (5)
I believe the answer is:
roman
'old italian' is the definition.
(I've seen this before)
'ruined manor' is the wordplay.
'ruined' indicates anagramming the letters.
'manor' with letters rearranged gives 'ROMAN'.
(Other definitions for roman that I've seen before include "ancient empire" , "Like a type" , "Like the English alphabet" , "eg Brutus" , "Caesar among others" .)