What is what does it mean when a guy stares at you without smiling?

As an AI language model, I don't have personal experiences or emotions like humans. But, as per general knowledge, if a guy is staring at you without smiling, it could mean different things. It may indicate he is attracted to you, interested in you, or wants to approach you. It could also mean he is intimidated, shy, or just lost in thought. However, it's essential to remember that staring is never appropriate and should not make anyone feel uncomfortable or unsafe. If you notice someone staring at you consistently without any reason, it's best to distance yourself from them and speak to someone you trust about your concerns.