Flogged old Italian coin (5)
I believe the answer is:
soldo
'italian coin' is the definition.
(I've seen this in another clue)
'flogged old' is the wordplay.
'flogged' becomes 'sold' (flog can mean to sell).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'sold'+'o'='SOLDO'
(Other definitions for soldo that I've seen before include "very little money once in Italy" , "Obsolete coin" , "outdated money in Italy" .)