There are many synonyms for the phrase "breaking one's promise". Some of the most common include: reneging, disregarding, failing to honor, betraying, backtracking, abandoning, violating, and breaching. Each of these words conveys a sense of betrayal or dishonesty, and can be used to describe the act of failing to keep one's word. Whether intentional or accidental, breaking a promise can cause harm to relationships and erode trust. It is important to always strive to uphold our commitments and hold ourselves accountable for the promises we make.