Shortened copper post (6)
I believe the answer is:
office
'post' is the definition.
(I've seen this before)
'shortened copper' is the wordplay.
'shortened' means to remove the last letter.
'copper' becomes 'officer'.
'officer' with its final letter removed is 'OFFICE'.
(Other definitions for office that I've seen before include "Place for administration business" , "Subsidiary" , "Job - place of work" , "Where a white-collar worker works" , "professional business?" .)