Definitions
1.NounA person who does not believe in deities or gods.
A person who is certain that no deities exist or who thinks that the existence of deities can be disproven.
2.NounA person who is certain that no deities exist or who thinks that the existence of deities can be disproven.
3.NounA person who doubts the existence of deities (therefore, an agnostic may be considered an atheist).
4.NounAny person lacking belief in deities (including children who are unaware of religion).
5.NounA person who does not believe in a particular deity (but may believe in another deity).
6.NounA person who does not believe in any religion (not even a religion without gods); a nonreligious person.
7.AdjectiveOf or relating to atheists or atheism; atheistic.
8.VerbTo make someone an atheist.