Developing new ace perfume (7)
I believe the answer is:
nascent
'developing' is the definition.
(nascent means developing or just beginning)
'new ace perfume' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'ace' becomes 'a' (abbreviation).
'perfume' becomes 'scent' (synonyms).
'n'+'a'+'scent'='NASCENT'
(Other definitions for nascent that I've seen before include "Emerging, in the process of being born" , "Sent can (anag.)" , "Beginning to develop, embryonic" , "Starting existence" , "Starting to develop" .)