Arrogant supporter on way to enlightenment (6)
I believe the answer is:
brazen
'arrogant' is the definition.
(thesaurus)
'supporter on way to enlightenment' is the wordplay.
'supporter' becomes 'bra' (a bra gives support to breasts).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'way to enlightenment' becomes 'zen' (I've seen this in another clue).
'bra'+'zen'='BRAZEN'
(Other definitions for brazen that I've seen before include "Forward" , "Shameless (impudence)" , "Brassy and impudent." , "Shameless and bold - resembling brass" , "Boldly impudent" .)