Hear a gun shot broadside (8)
I believe the answer is:
harangue
'broadside' is the definition.
(both can mean an attack)
'hear a gun shot' is the wordplay.
'shot' indicates anagramming the letters.
'hear'+'a'+'gun'='hearagun'
'hearagun' with letters rearranged gives 'HARANGUE'.
(Other definitions for harangue that I've seen before include "A lengthy speech or diatribe" , "Lecture aggressively" , "A lengthy vehement speech, may be abusive" , "Loud angry speech" , "Loud and agressive speech" .)