In the past, atheism has been described as “lack of belief in God.” This in itself is a monotheistic definition of atheism. Atheists in fact dont believe in God or gods, spiritual or supernatural beings, or anything else of the sort.

Is an atheist someone who doesnt believe in God?

An atheist doesnt believe in a god or divine being. Atheism is the doctrine or belief that there is no god. However, an agnostic neither believes nor disbelieves in a god or religious doctrine.