Forbid government head making a report (4)
I believe the answer is:
bang
'a report' is the definition.
(report can mean a loud noise)
'forbid government head' is the wordplay.
'forbid' becomes 'ban' (banning is a kind of forbiding).
'head' indicates taking the first letters.
The first letter of 'government' is 'g'.
'ban'+'g'='BANG'
'making' is the link.
(Other definitions for bang that I've seen before include "Slam" , "Strike violently" , "Sudden impact" , "Sudden loud noise like an explosion" , "Gun sound" .)