Don’t allow to leave the report unfinished (3)
I believe the answer is:
ban
'don't allow to' is the definition.
I can't tell whether this definition defines the answer.
'the report unfinished' is the wordplay.
'the report' becomes 'bang' (I've seen this before).
'unfinished' means to remove the last letter.
'bang' with its last letter taken away is 'BAN'.
'leave' is the link.
Can you help me to learn more?
(Other definitions for ban that I've seen before include "Exile" , "Stop" , "Officially prohibit" , "the calling of young vassals" , "'Forbid, prohibit (3)'" .)