Exile's collar turned up (3)
I believe the answer is:
ban
'exile's' is the definition.
(thesaurus)
'collar turned up' is the wordplay.
'collar' becomes 'nab' (both can mean to catch a person).
'turned up' says the letters should be written in reverse.
'nab' written backwards gives 'BAN'.
(Other definitions for ban that I've seen before include "Veto" , "Censor or proscribe" , "Bar, prohibition" , "Hungarian governor < to forbid" , "'Forbid, prohibit (3)'" .)