exponent

nouns

a person who pleads for a cause or propounds an idea
advocate, advocator, exponent, proponent
someone who expounds and interprets or explains
exponent
is derived from
expound
is a type of (narrower)
a person who uses the mind creatively
intellect, intellectual
a mathematical notation indicating the number of times a quantity is multiplied by itself
exponent, index, power
is derived from
exponential