Supporting a Mountie, perhaps, with free study (6)
I believe the answer is:
ridden
'supporting a mountie perhaps' is the definition.
(Mounties are horse-riding Canadian police officers)
'with free study' is the wordplay.
'with' is a charade indicator (letters next to each other).
'free' becomes 'rid' ('rid' can be a synonym of 'free').
'study' becomes 'den' (I've seen this before).
'rid'+'den' is 'RIDDEN'.
(Other definitions for ridden that I've seen before include "(Of a horse) sat upon" , "What horses often are" , "Used for transport" , "(Of horse) mounted" , "Oppressed" .)