A violation of an oath is a serious offense that can have legal and personal consequences. Some synonyms for this include breach of promise, breaking one's word, defying a pledge, and reneging on an agreement. Other terms that can be used to describe a violation of an oath include perjury, falsehood, dishonesty, and deception. It is essential to remember that breaking an oath or vow is not only unethical but can also lead to a loss of trust, broken relationships, and legal repercussions. This is why it is essential to respect and honor our promises and deters from violating any oaths that we make.