What is hung up?

Hung up is a phrase that is commonly used to describe a situation where someone is refusing to end a phone call or communication with another person. It is often seen as a frustrating or irritating behavior, as the person refusing to end the communication can cause the other person to feel as though they are unable to move on with their day or handle other tasks. In some cases, hanging up on someone can also be a sign of anger or frustration, and may be used in order to express dissatisfaction or hostility towards another person.