1. Incredulity; the withholding of belief; as, unbelief is blind.

2. Infidelity; disbelief of divine revelation.

3. In the New Testament, disbelief of the truth of the gospel, rejection of Christ as the Savior of men, and of the doctrines he taught; distrust of God's promises and faithfulness, etc. Matthew 13:58; Mark 16:14; Hebrews 3:12; Romans 4:20.

4. Weak faith. Mark 9:24.