Discontinue supporting miscreant (8)
I believe the answer is:
prorogue
'discontinue' is the definition.
(I've seen this before)
'supporting miscreant' is the wordplay.
'supporting' becomes 'pro' (I've seen this in another clue).
'miscreant' becomes 'rogue' (I've seen this in another clue).
'pro'+'rogue'='PROROGUE'
(Other definitions for prorogue that I've seen before include "Suspend meeting" , "Discontinue meeting" , "Stop meeting" , "Discontinue (a session of parliament)" , "Suspend, postpone" .)