Infidel (noun)

1. A person who does not believe in a particular religion, especially Christianity or Islam.
2. A person who is regarded as morally or spiritually unconvinced.

Origin:

Infidel comes from the latin word infidelis meaning "unfaithful" or "not a believer".

Examples:

1. During the crusades, infidels were seen as enemies by the Christians.
2. The religious leader deemed all non-believers as infidels.
3. During the inquisition, many were accused of being infidels and were punished.
4. He considered himself as an infidel and did not believe in any organized religion.
5. The infidel was seen as a threat to the established religious order.