An aroma rising (6)
I believe the answer is:
ascent
'rising' is the definition.
(thesaurus)
'an aroma' is the wordplay.
'an' becomes 'a'.
'aroma' becomes 'scent' ('scent' can be a synonym of 'aroma').
'a'+'scent'='ASCENT'
(Other definitions for ascent that I've seen before include "A climb or way up" , "A rise in status; climb" , "Upward journey" , "rising?" , "advancement" .)