Doing otherwise making some block (5)
I believe the answer is:
ingot
'block' is the definition.
(I know that ingot is a type of block)
'doing otherwise making some' is the wordplay.
'some' indicates the answer is hidden within the clue.
'INGOT' can be found hidden inside 'doing otherwise making'.
(Other definitions for ingot that I've seen before include "Cast metal obtained from a mould" , "Mass of cast metal" , "Moulded metal bar" , "Pig" , "Mass of unwrought gold, for instance" .)