Nonbeliever (noun)

A person who does not believe in a particular religion or system of belief.

Origin:

Non- + believer.

Examples:

1. He was a nonbeliever and did not attend religious services.
2. The nonbelievers were not included in the religious rituals.
3. She considered herself a nonbeliever and did not believe in any deities.
4. The group was made up of both believers and nonbelievers.
5. He felt that nonbelievers were not given the same rights as believers.