Operatic air (4)
I believe the answer is:
aria
'operatic air' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aria that I've seen before include "Operatic part" , "Piece of music" , "Summertime perhaps" , "Song from an opera (4)" , "Song, one from 'West Side Story' needing no introduction" .)