Open University introducing smart purge (7)
I believe the answer is:
ousting
'purge' is the definition.
(thesaurus)
'open university introducing smart' is the wordplay.
'open university' becomes 'OU'.
'introducing' is a charade indicator (letters next to each other) (some letters go before others).
'smart' becomes 'sting' (both can mean to burn or hurt).
'ou'+'sting'='OUSTING'
(Other definitions for ousting that I've seen before include "Evicting" , "Driving out" , "ejecting" , "Turfing out" .)