The role of the oddball? (9)
I believe the answer is:
character
This clue is a double definition.
'the role' is the first definition.
(synonyms)
'the oddball?' is the second definition.
(thesaurus)
'of' acts as a link.
(Other definitions for character that I've seen before include "Part" , "Letter; personality" , "card" , "strength of mind" , "Letter or number" .)