Infamous Roman (4)
I believe the answer is:
nero
'infamous roman' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nero that I've seen before include "Cruel Roman emperor" , "Fiddling Roman emperor" , "Emperor (who fiddled while Rome burned?) d. AD68" , "Ruler" , "Roman 9" .)