Perfume on its way, it’s said (5)
I believe the answer is:
scent
'perfume' is the definition.
(I know that perfume can be written as scent)
'on its way it's said' is the wordplay.
'on its way' becomes 'sent' (sent in the post).
'it's said' shows a homophone (sound like).
'sent' sounds like 'SCENT'.
(Other definitions for scent that I've seen before include "Number of clues" , "Pleasant smell" , "Whiff" , "Get wind of" , "Track; aroma" .)