The phrase "were faithful" suggests loyalty, commitment, and trustworthiness. Its antonyms, on the other hand, would convey the opposite meaning. Words like disloyal, unfaithful, treacherous, deceitful, and perfidious reflect a lack of trust, reliability, and integrity. These antonyms carry negative connotations and imply a breach of trust, such as infidelity in a relationship, betrayal of a friend, or breaking a promise. Synonyms like dishonest or insincere also suggest a lack of faithfulness, albeit in more subtle ways. Using antonyms for "were faithful" can help highlight the importance of trust and loyalty in personal relationships, professional partnerships, and other areas of life.