Erudite drunk holding court? Goodness! (9)
I believe the answer is:
rectitude
'goodness' is the definition.
(thesaurus)
'erudite drunk holding court?' is the wordplay.
'drunk' indicates anagramming the letters.
'holding' means one lot of letters goes inside another.
'court?' becomes 'ct'.
'erudite' anagrammed gives 'reitude'.
'reitude' enclosing 'ct' is 'RECTITUDE'.
(Other definitions for rectitude that I've seen before include "Strict propriety" , "Certitude about moral goodness" , "Uprightness, integrity" , "Correctness" , "Moral integrity" .)