Vocalist in boy group’s initial worry (10)
I believe the answer is:
songstress
'vocalist in boy' is the definition.
'songstress' can be an answer for 'vocalist' (songstress is a kind of vocalist). I'm not certain of the 'in boy' bit.
'group's initial worry' is the wordplay.
'group's initial' becomes 'song' (I can't justify this - if you can you should believe this answer much more).
'worry' becomes 'stress' (I've seen this before).
'song'+'stress'='SONGSTRESS'
Can you help me to learn more?
(Other definitions for songstress that I've seen before include "coloratura perhaps" , "Soprano perhaps" , "Woman making up the numbers" , "performer" , "Female singer" .)