Singer in traditional top (4)
I believe the answer is:
alto
'singer' is the definition.
(alto is a kind of singer)
'in traditional top' is the wordplay.
'in' says the answer is hidden in the clue.
'ALTO' is hidden within 'traditional top'.
(Other definitions for alto that I've seen before include "Second of four parts (in singing)" , "someone to sing" , "A singing voice or pitch" , "Member of choir" , "Key old > male who scores high" .)