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.
Facts
[Gentlemen's Alliance Cross] - book gives out the word Heretic means used from Japan.