Informal vote of prohibition (4)
I believe the answer is:
veto
'prohibition' is the definition.
(I've seen this before)
'informal vote' is the wordplay.
'vote' can be anagrammed to 'VETO'.
However, I'm unsure how this is indicated.
'of' is the link.
Can you help me to learn more?
(Other definitions for veto that I've seen before include "Vote to block a decision" , "Right to prevent proposed action" , "Stop" , "A confused vote, altogether negative" , "Right to reject a proposed measure" .)