Outlaw needing good report (4)
I believe the answer is:
bang
'report' is the definition.
(report can mean a loud noise)
'outlaw needing good' is the wordplay.
'outlaw' becomes 'ban' (banning is a kind of outlawing).
'needing' means one lot of letters go next to another.
'good' becomes 'g' (abbreviation).
'ban'+'g'='BANG'
(Other definitions for bang that I've seen before include "Vigorous blow" , "Slam" , "Report - something the hairdresser did?" , "hit" , "Explosion; hair fringe" .)