The phrase "swore down" means to make a solemn vow or take an oath to do something. Antonyms for this phrase indicate the opposite meaning. Some of the antonyms for "swore down" include lying, breaking one's word, neglecting to do something, or failing to fulfill a promise. Other antonyms for this phrase might include phrases like "relaxed," "let go," or "forgot about." The opposite of "swore down" is typically a phrase that denotes a lack of commitment or failure to follow through on a promise, whether intentionally or unintentionally.