Weakness (noun)

The quality or state of being weak, lack of strength or effectiveness.

Origin:

Middle english: from old norse veikr "weak" + -ness.

Examples:

1. Her weakness was a result of the illness.
2. The economy's weakness has been exacerbated by high unemployment.
3. The company's biggest weakness is its lack of innovation.
4. His weakness for chocolate is well-known.
5. The weakness in the bridge's structure was apparent during the inspection.