Answer:
Monotheism or Monotheistic = one God
Polytheism or Polytheistic = many gods
Atheism or Atheistic = Don't believe in God
Explanation:
Monotheistic is a religion such as Christianity, Polytheistic is a religion like Buddhism, and Atheistic is where one does not believe in God (not to be mixed up with Agnostic people, who don't claim belief or disbelief of there being a God)
