Hear a gun shot in lecture (8)
I believe the answer is:
harangue
'lecture' is the definition.
(I've seen this before)
'hear a gun shot' is the wordplay.
'shot' is an anagram indicator.
'hear'+'a'+'gun'='hearagun'
'hearagun' with letters rearranged gives 'HARANGUE'.
'in' is the link.
(Other definitions for harangue that I've seen before include "Declamation - lecture" , "Highly charged speech" , "Tirade, diatribe" , "A lengthy speech or scolding" , "'Loud, long diatribe (8)'" .)