Blacksmith's block (5)
I believe the answer is:
anvil
'blacksmith's block' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for anvil that I've seen before include "Block on which metals are hammered" , "Block for metalworking" , "On which hot metal is shaped" , "It helps forger" , "part of the ear" .)