Rogue sporting cardinal hat ousts DI (9)
I believe the answer is:
charlatan
'rogue' is the definition.
(thesaurus)
'sporting cardinal hat ousts di' is the wordplay.
'sporting' is an anagram indicator.
'ousts' indicates named letters should be taken away.
'cardinal'+'hat'='cardinalhat'
'cardinalhat' with 'di' removed is 'carnalhat'.
'carnalhat' with letters rearranged gives 'CHARLATAN'.
(Other definitions for charlatan that I've seen before include "Impostor, quack" , "Deceiver who attracts customers with tricks or jokes" , "ake" , "fake" , "Person who falsely claims to be an expert" .)