What is what does it mean when a guy says goodnight?

When a guy says "goodnight" to someone, it usually means that he is indicating that he is going to bed or ending his conversation for the night. It is typically a polite way of communicating that someone wishes to end the interaction and is leaving the conversation for the time being. Additionally, saying goodnight can sometimes be a sign of respect towards the person, indicating that they hold value in the person's life and that they wish them well for the rest of the night. Overall, saying goodnight is a simple and polite way to express a desire to end a conversation and show consideration towards the other person.