heréjo (Franco-Provençal) comes from Latin haereticus, from Ancient Greek αἱρετῐκός, from Ancient Greek αἱρέω, from Proto-Hellenic həřřéyō, from Proto-Indo-European sēr-, from Proto-Indo-European ser- — to flow; to guard; to bind, to tie together.
heréjo (Franco-Provençal): heretic