The role of Nature? (9)
I believe the answer is:
character
I believe this clue is a double definition.
'the role' is the first definition.
(synonyms)
'nature?' is the second definition.
(a person's nature or condition)
'of' acts as a link.
(Other definitions for character that I've seen before include "Sign" , "strength of mind" , "case" , "Distinctive nature" , "Eccentric person" .)