1. In general, want of faith or belief; a withholding of credit.

2. Disbelief of the inspiration of the Scriptures, or the divine original of christianity; unbelief.

There is no doubt that vanity is one principal cause of infidelity.

3. Unfaithfulness, particularly in married persons; a violation of the marriage covenant by adultery or lewdness.

4. Breach of trust; treachery; deceit; as the infidelity of a friend or a servant. In this sense, unfaithfulness is most used.