The concept of two-timing refers to a person who is unfaithful or disloyal in a relationship, often having multiple romantic partners at the same time. Some antonyms for the word two-timing include loyalty, faithfulness, and commitment. These words imply an unwavering dedication to one partner and a refusal to engage in deceitful or dishonest behavior. Another antonym is monogamy, which refers to the practice of having one romantic partner at a time. Overall, antonyms for two-timing reflect values such as trust, honesty, and respect in romantic relationships.