agnostic — An agnostic believes that it is not possible to know whether God exists or not. Compare atheist.
atheist — An atheist is a person who believes that there is no God. Compare agnostic.
doubter — to be uncertain about; consider questionable or unlikely; hesitate to believe.
freethinker — a person who forms opinions on the basis of reason, independent of authority or tradition, especially a person whose religious opinions differ from established belief.
heathen — (in historical contexts) an individual of a people that do not acknowledge the God of the Bible; a person who is neither a Jew, Christian, nor Muslim; a pagan.
heretic — a professed believer who maintains religious opinions contrary to those accepted by his or her church or rejects doctrines prescribed by that church.
iconoclast — a person who attacks cherished beliefs, traditional institutions, etc., as being based on error or superstition.
idolater — Also, idolist [ahyd-l-ist] /ˈaɪd l ɪst/ (Show IPA). a worshiper of idols.
infidel — Religion. a person who does not accept a particular faith, especially Christianity. (in Christian use) an unbeliever, especially a Muslim. (in Muslim use) a person who does not accept the Islamic faith; kafir (def 2).
pantheist — the doctrine that God is the transcendent reality of which the material universe and human beings are only manifestations: it involves a denial of God's personality and expresses a tendency to identify God and nature.
polytheist — the doctrine of or belief in more than one god or in many gods.
scoffer — to speak derisively; mock; jeer (often followed by at): If you can't do any better, don't scoff. Their efforts toward a peaceful settlement are not to be scoffed at.
skeptic — a person who questions the validity or authenticity of something purporting to be factual.
