An antonym for the word "promise" would be "abandon." While making a promise means commitment and assurance, the act of abandoning something indicates a lack of such commitment. Other antonyms for "promise" include "deny", "break", "refuse", and "ignore". These words all suggest a lack of trust, honesty and reliability. It is important to keep promises as it builds trust and credibility between people, while breaking them can cause severe damage to relationships. Therefore, it is essential to be mindful of our words and actions, to make promises we can keep, and to avoid making unrealistic promises in order to maintain trust and respect.