Block hidden by Italian villa (5)
I believe the answer is:
anvil
'block' is the definition.
(anvil is a kind of block)
'hidden by italian villa' is the wordplay.
'hidden' indicates the answer is hidden within the clue.
'ANVIL' is hidden in the letters of 'by italian villa'.
(Other definitions for anvil that I've seen before include "Bone" , "Block for metalworking" , "Heavy block on which to hammer metal" , "Block in smithy" , "Smithy's block" .)