Failing (noun)

1. A failure or lack of success; a shortcoming or deficiency.
2. A defect or weakness in something or someone.

Origin:

From the verb "to fail" (old english feallan) which means "to fall short" or "to be lacking".

Examples:

1. The failing of the dam was a catastrophic event.
2. His failing as a leader was a major contributing factor to the company's downfall.
3. She identified several areas where the company had significant failings.
4. He acknowledged his own personal failing and promised to work on improving himself.
5. The failing of the brakes caused the accident.