Where does “haeretice” come from?

haeretice (Latin) 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.

haeretice (Latin): with heretical opinions, heretically; vocative...