A "nonbeliever" is someone who does not believe in a specific idea, concept, or religion. They might have doubts or simply choose not to believe in something. Full definition
Other common religious teachings, such as those that promote the same ethical treatment of nonbelievers as of believers, prohibit compulsory religious belief, or acknowledge the legitimacy of rebellion against tyranny, build upon these cornerstones. (religion-online.org)
He seemed to touch a lot of nonbelievers in a highly moral, aspiring way. (firstthings.com)
Which is better, a milquetoast church filled with nonbelievers who congratulate themselves on their Christianity or a church with no walls that is accused of loving and serving sinners? (redeeminggod.com)