infidelityсуществительное The act or state of being unfaithful to a spouse or partner, typically involving a sexual relationship with someone else. Their marriage ended due to his infidelity.
A lack of loyalty or faithfulness to a person, cause, or belief. The politician's infidelity to his campaign promises disappointed many voters.
The rejection of or lack of belief in a particular religion, especially Christianity; unbelief. In the seventeenth century, accusations of infidelity could lead to severe punishment for alleged heretics.