I can not think of a better response to this question than what Hank Fox said:
“Say you’re talking about slavery, there are two ways you can look at it. You can see it as a social phenomenon, or you can see it as a personal condition.
In SOCIAL terms, the opposite of slavery is anti-slavery.
But in PERSONAL terms, the opposite of slavery is freedom.
A man freed from slavery is not just a non-slave. He’s a FREE MAN. The one implies a restrictive, walled-in life determined by the will of someone else. The other implies not just a non-slave, but a person faced with infinite possibility, someone who can do anything HE likes with his life. Slavery is a small box; freedom is the universe of self-determined choices outside it.
Likewise with religion, you can see it as a social phenomenon, or as a personal condition.
In social terms, the opposite of religion can be called atheism. But in personal terms, the opposite of religion is, again, freedom. Freedom of thought, freedom of choice, freedom of … everything.
Just like slavery, religion is a small box. Freeing yourself from that box presents you with infinite possibilities.
Because they’re the words most people know, I’ll probably still use the terms “atheism” and “atheist” to describe myself and my non-theistic beliefs. But I’m gonna try more often to also define myself and my fellow atheists in these grander terms: We’re free men. Free women. Free thinkers. Free selves. With all the universe of self-willed choices, thoughts and possibilities that implies.”