Old Italian obliterated manor (5)
I believe the answer is:
roman
'old italian' is the definition.
(I've seen this before)
'obliterated manor' is the wordplay.
'obliterated' is an anagram indicator.
'manor' is an anagram of 'ROMAN'.
(Other definitions for roman that I've seen before include "From Italy's capital" , "Dominant political power of first centuries AD" , "Plain upright print style" , "Printing style" , "Caesar among others" .)