Heretic is a popular word in the game called Final Fantasy Tactics. The word is used agents a male name Ramza Beoulve. The Japanese term for "Heretic" is gedo, It is a Buddhist term that means "those who have stayed from the true path."
Meaning those who have stayed from the true path other terms means someone agents it or don't agree.
[Gentlemen's Alliance Cross] - book gives out the word Heretic means used from Japan.