Boy holding ring for girl (5)
I believe the answer is:
carol
'girl' is the definition.
'boy holding ring' is the wordplay.
'boy' becomes 'carl' (**).
'holding' is an insertion indicator.
'ring' becomes 'o'.
'carl' placed around 'o' is 'CAROL'.
'for' acts as a link.
(Other definitions for carol that I've seen before include "Song, especially at Christmas" , "Song celebrating the birth of Jesus" , "Girl's name; sing" , "Religious song - girl's name" , "Girl" .)