A fringe explosion (4)
I believe the answer is:
bang
I believe this clue is a double definition.
'a fringe' is the first definition.
(I've seen this before)
'explosion' is the second definition.
(I've seen this in another clue)
(Other definitions for bang that I've seen before include "Slam" , "Sudden impact" , "Completely modern" , "Sound of a gunshot" , "Explosion; hair fringe" .)