What is the antonym for the word monotheism?

Answer 1

first of all mono is not a word, it is a prefix. Its opposite is multi.

edit: mono is the colloquial name for mononucleosis so it CAN be a word

as a prefix, a more proper opposite is "poly" and not "multi"

Answer 2

There is no antonym for the word "Monotheism" however there are many contrary points of view which could be substituted as pseudo-antonyms if you will. Words like "Polytheism" the belief in many gods, "Atheism" the belief that there are no gods.

Or if you want to get perfectly accurate, adding an "a" to the beginning makes it mean the opposite, so while "Monotheism" is belief in one god, "Amonotheism" is /not/ belief in one god. Although that's a new word I just invented for this purpose.