Belonging to the older local practices rather than the established religion. Its root means of the countryside — the belief that stayed where people lived.
Latin paganus (a villager, country-dweller, civilian), from pagus (a rural district); Christianity's word for the older local religions it displaced was first simply the word for the countryside itself, where the older ways stayed longest.
Belonging to older, local ways of belief rather than to the religion that displaced them — a word for the countryside they went on being practiced in.