Breach

Dictionary Definition

1. n. literally, a break. A breach may be a failure to perform a contract (breaking its terms), failure to do one’s duty (breach of duty, or breach of trust), causing a disturbance, threatening, or other violent acts which break public tranquillity (breach of peace), illegally entering property (breach of close), not telling the truth-knowingly or innocently-about title to property (breach of warranty), or, in past times, refusal to honor a promise to marry (breach of promise).
2. v. the act of failing to perform one’s agreement, breaking one’s word, or otherwise actively violating one’s duty to other.