One of my favorite etymologies (this is how you know I’m a nerd) is that of the word “heretic.” Merriam-Webster defines heretic as:
1: a dissenter from established religious dogma; especially: a baptized member of the Roman Catholic Church who disavows a revealed truth
2: one who dissents from an accepted belief or doctrine: see also NONCONFORMIST
There’s a negative connotation, though–as anyone who dissents from the established doctrine is therefore “rocking the boat” and otherwise causing trouble and contributing to the decline of the establishment.
So it’s wonderful that this word should come (in a long and complicated journey) from the Greek hairetikos–“able to choose.“