Ignorance (noun)

1. The state of being ignorant; lack of knowledge or information.
2. Lack of education or knowledge; the condition of being uneducated or uninformed.

Origin:

The word ignorance comes from the old french word ignorance, which comes from the latin word ignorare, which means "not to know".

Examples:

1. His ignorance of the subject was obvious.
2. Her ignorance of the issue was concerning.
3. His ignorance was no excuse for his behavior.
4. The ignorance of the law is not a defense.
5. The ignorance of the public was exploited by the politician.