Part of forge in Roman villa (5)
I believe the answer is:
anvil
'part of forge' is the definition.
('anvil' is part of 'forge')
'in roman villa' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ANVIL' can be found hidden inside 'roman villa'.
(Other definitions for anvil that I've seen before include "part of the ear" , "hard block" , "Forging block" , "One frequently gets hammered" , "Verdi chorus from Il Trovatore" .)