INFIDEL'ITY, noun [Latin infidelitas.] 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.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI