Musical form Gounod normally holds back (5)
I believe the answer is:
rondo
'musical form' is the definition.
(I've seen this before)
'gounod normally holds back' is the wordplay.
'holds' indicates the answer is hidden within the clue.
'back' is a reversal indicator.
'odnor' is hidden within 'gounod normally'.
'odnor' back-to-front is 'RONDO'.
(Other definitions for rondo that I've seen before include "Piece written" , "has repetitive theme" , "Type of movement" , "Musical composition with a recurring theme" , "Musical piece with a recurring theme" .)