Smithy's block (5)
I believe the answer is:
anvil
'smithy's block' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for anvil that I've seen before include "Forging block" , "One frequently gets hammered" , "Metalworker's block" , "On which hot metal is shaped" , "Bone" .)