Trilling performance? (4)
I believe the answer is:
aria
'trilling performance?' 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 "Air in an opera" , "Song for solo voice from an oratorio, cantata etc" , "Musical performance" , "Operatic number" , "Operatic solo performance" .)