Singer in white, normally (5)
I believe the answer is:
tenor
'singer' is the definition.
(tenor is a kind of singer)
'in white normally' is the wordplay.
'in' indicates a hidden word.
'TENOR' is hidden in the letters of 'white normally'.
(Other definitions for tenor that I've seen before include "Vocal range" , "Male voice (one of three?)" , "High male singing voice like Pavarotti" , "General drift or meaning" , "thread" .)