Boys quibbled about firework (5)
I believe the answer is:
squib
'firework' is the definition.
(squib is a kind of firework)
'boys quibbled about' is the wordplay.
'about' indicates the answer is hidden within the clue.
'SQUIB' is hidden in the letters of 'boys quibbled'.
(Other definitions for squib that I've seen before include "Firework, burns with a fizzing noise" , "piece of satire" , "Small explosive, often damp" , "Firework (perhaps damp!)" , "Firework (disappointing, if damp)" .)