1) the state of not believing (disbelief)
2) showing idealism; believing in, based on, the idea that perfect standards are possible (and so often impractical) (idealistic)
3) the state of not believing something (incredulity)
of which there is no possible doubt
confident
too ready to believe things
gullible, naive
of God or religion
religious, sacred
true and faithful
faithful, dependable
of religion; (of a person) devout; having faith; (doing work, duties) very carefully
concerning belief in divinity