违约 (wéi yuē) literally means 'to violate an agreement' — 违 (wéi) means 'to violate, go against', and 约 (yuē) means 'agreement, contract, or covenant'. Together, they form a formal, legal term meaning 'to breach a contract' — that is, to fail to fulfill one's obligations under a binding agreement. It is commonly used in business, real estate, employment, and service contexts where written or verbal contracts exist.

This word carries a serious, often negative connotation: it implies legal or financial consequences, such as penalties or lawsuits. While it can refer to any broken promise, in practice it almost always appears in formal or semi-formal settings — not casual conversations. It’s frequently paired with words like 责任 (zérèn, liability), 金 (jīn, fine/penalty), or 处理 (chǔlǐ, handling/resolution). The verb is typically used transitively (e.g., 违约了, 违约责任), and rarely stands alone without context indicating which party or what terms were breached.