Pioneer not vain or fake (9)
I believe the answer is:
innovator
'pioneer' is the definition.
('innovator' can be a synonym of 'pioneer')
'not vain or fake' is the wordplay.
'fake' is an anagram indicator.
'not'+'vain'+'or'='notvainor'
'notvainor' with letters rearranged gives 'INNOVATOR'.
(Other definitions for innovator that I've seen before include "Maker of change" , "Fresh thinker" , "new ideas man" , "Person who devises a new way of doing things" , "Pioneer" .)