Perfume was posted, we hear (5)
I believe the answer is:
scent
'perfume' is the definition.
(I know that perfume can be written as scent)
'posted we hear' is the wordplay.
'posted' becomes 'sent' ('send' can be a synonym of 'post').
'we hear' shows a homophone (sound like).
'sent' is a homophone of 'SCENT'.
'was' is the link.
(Other definitions for scent that I've seen before include "Distinctive smell" , "Clue" , "Track; aroma" , "Number of clues" , "Get wind of" .)