Answer:
syncretism
Step-by-step explanation:
Religious syncretism exhibits blending of two or more religious belief systems into a new system, or the incorporation into a religious tradition of beliefs from unrelated traditions. It is contrasted by the idea of multiple religious belonging and polytheism, respectively.
This can occur for many reasons, and the latter scenario happens quite commonly in areas where multiple religious traditions exist in proximity and function actively in the culture, or when a culture is conquered, and the conquerors bring their religious beliefs with them, but do not succeed in entirely eradicating the old beliefs or, especially, practices.
Religions may have syncretic elements to their beliefs or history, but adherents of so-labeled systems often frown on applying the label, especially adherents who belong to "revealed" religious systems, such as the Abrahamic religions, or any system that exhibits an exclusivist approach. Such adherents sometimes see syncretism as a betrayal of their pure truth. By this reasoning, adding an incompatible belief corrupts the original religion, rendering it no longer true. Indeed, critics of a specific syncretistic trend may sometimes use the word "syncretism" as a disparaging epithet, as a charge implying that those who seek to incorporate a new view, belief, or practice into a religious system actually distort the original faith. The consequence, according to Keith Ferdinando, is a fatal compromise of the dominant religion's integrity.[1] Non-exclusivist systems of belief, on the other hand, may feel quite free to incorporate other traditions into their own.