Punish devious cheats to a point (7)
I believe the answer is:
chasten
'punish' is the definition.
(thesaurus)
'devious cheats to a point' is the wordplay.
'devious' is an anagram indicator.
'to a point' becomes 'n' (N is an example**).
'cheats' with letters rearranged gives 'chaste'.
'chaste'+'n'='CHASTEN'
(Other definitions for chasten that I've seen before include "Subdue - a stench (anag)" , "Castigate or punish" , "Suppress" , "Subdue the pride of, discipline" , "Subdue, correct by punishing" .)