In Chinese culture, where social networks and relationships (关系, guānxi) are paramount, the act of 绝交 is a profound and heavy decision. Maintaining social harmony is a key cultural value, so openly breaking a relationship is seen as a last resort and a very serious step. A helpful Western comparison is the difference between “ghosting” someone and sending a formal letter of resignation. “Ghosting” or “unfriending” on social media is a passive, often ambiguous way of ending contact. 绝交, on the other hand, is an active, unambiguous declaration. It often involves a direct confrontation or a clear message stating the intention to end the relationship. It signifies that a serious breach of trust or loyalty (义气, yìqì) has occurred, causing a significant loss of face (面子, miànzi) for one or both parties. To 绝交 is to say that the relationship is so broken that even the pretense of harmony is no longer possible.
绝交 is a formal and emotionally charged word. You won't hear it used casually.