What is the meaning of Atheist?

A person who does not believe in deities or gods.

1. A person who is certain that no deities exist or who thinks that the existence of deities can be disproven.

   A person who is certain that no deities exist or who thinks that the existence of deities can be disproven.

   A person who doubts the existence of deities (therefore, an agnostic may be considered an atheist).

   Any person lacking belief in deities (including children who are unaware of religion).

   A person who does not believe in a particular deity (but may believe in another deity).

   A person who does not believe in any religion (not even a religion without gods); a nonreligious person.

   Of or relating to atheists or atheism; atheistic.

   To make someone an atheist.

   alternative form of ateist

   Source: wiktionary.org