free-think-er n. A person who forms opinions about religion on the basis of reason, independently of tradition, authority, or established belief. Freethinkers include atheists, agnostics and rationalists.
No one can be a freethinker who demands conformity to a bible, creed, or messiah. To the freethinker, revelation and faith are invalid, and orthodoxy is no guarantee of truth.
So a freethinker includes atheist, agnostic, and rationalist. Neither of which believe in a god. Sure I made a mistake when I said it was only atheist.
Also only a close minded person would be to blind to see that there isn't enough evidence of god to just accept there is one. An open minded person is someone who doesn't bleive in a god and includes atheist and agnostic.
A good site about what a freethinker is.
Freedom From Religion Foundation