Send from the office (4)
I believe the answer is:
post
I believe this clue is a double definition.
'send' is the first definition.
(to send in the post)
'the office' is the second definition.
(synonyms)
'from' acts as a link.
(Other definitions for post that I've seen before include "Stake; appointment" , "type of support" , "employment" , "Job; upright timber" , "Send via the mail" .)