Sodium smell emerging (7)
I believe the answer is:
nascent
'emerging' is the definition.
(synonyms)
'sodium smell' is the wordplay.
'sodium' becomes 'NA' (Na is the chemical symbol for sodium).
'smell' becomes 'scent' (scent is a kind of smell).
'na'+'scent'='NASCENT'
(Other definitions for nascent that I've seen before include "Beginning to show signs of potential" , "coming into circulation?" , "Sent can (anag.)" , "Emerging, in the process of being born" , "starting to mature" .)