The act of going back on one's word is often referred to as reneging, breaking a promise, or simply, lying. Antonyms for this phrase can include words such as sincere, trustworthy, dependable, and honest. These words reflect the opposite meaning of going back on one's word, conveying a sense of reliability and truthfulness. It is important to keep one's word, as it builds trust and shows respect for others. By using antonyms to describe this negative behavior, we emphasize the importance of keeping promises and staying true to our word in all aspects of life.