Unbelieving (adjective)

Not having faith or belief in something.

Origin:

From un- + believing.

Examples:

1. He gave an unbelieving look when I told him the news.
2. The unbelieving crowd did not accept the evidence presented.
3. She gave an unbelieving shake of her head when I told her the story.
4. He was an unbelieving atheist and did not believe in any god.
5. His unbelieving attitude made it hard for him to accept new ideas.