Shocking report? (4)
I believe the answer is:
bang
'report?' is the definition.
(report can mean a loud noise)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for bang that I've seen before include "Completely modern" , "Sudden noise; fringe" , "Explosive noise" , "Slam" , "Fringe - report" .)