1) a person who does not believe in the existence of god(s)
2)high school student that believes the lack off faith in a deity grants them the right to behave like a complete asshole that gets easily offended if someone of authority says something like "God help us."
1) atheist: *sneeze*
man: God bless you
atheist: I'm an atheist, i don't believe in God
man: Then, gesundheit
2) Teacher: Only God himself can help this class's grades
atheist: Don't say God, some people might not believe in God
Teacher: If you want people to respect your beliefs you have to respect theirs, and I believe in God so please do not insult my faith and I won't insult yours... or lack there of.