
Exponent
Public Advocacy
 Exponent here means actively and openly supporting a cause, like a public figure. 
She became a renowned exponent of women's rights.
 Not Always Famous
 An exponent can be any person who declares their support, not necessarily famous. 
A local teacher might be an exponent of educational reform.
 Positive Connotation
 Using 'exponent' often implies admiration for the person's dedication. 
Her grandfather was a respected exponent of free speech.