doubt, doubtfulness, dubiety, dubiousness, incertitude, uncertainty - the state of being unsure of something

cognitive content, mental object, content - the sum or range of what has been perceived, discovered, or learned

scepticism, skepticism, agnosticism - the disbelief in any claims of ultimate knowledge

atheism - a lack of belief in the existence of God or gods

heresy, unorthodoxy - a belief that rejects the orthodox tenets of a religion