What is what does it mean when a guy leaves you on open?

When a guy leaves you on open, it means that he has read your message, but he is not responding or acknowledging your message. This can be interpreted in different ways depending on the circumstances and the relationship between you and the guy. It can mean that he is busy with something else, not interested in you or the conversation, or he doesn't know what to say. Leaving someone on open can also be a way of avoiding confrontation or ending the conversation without having to say anything. However, it can also be considered rude or disrespectful if it happens frequently or without any explanation.