A Liberal on stage is sanctioned (5)
I believe the answer is:
legal
'is sanctioned' is the definition.
('legal' can be similar in meaning to 'sanctioned')
'a liberal on stage' is the wordplay.
'a liberal' becomes 'al' (I've seen this in other clues).
'on' is a charade indicator (letters next to each other).
'stage' becomes 'leg' ('leg' can be a synonym of 'stage').
'al' put after 'leg' is 'LEGAL'.
(Other definitions for legal that I've seen before include "In accordance with statute" , "Within bounds of law" , "Authorized" , "not breaking the law" , "Compliant with the law" .)