I sent a message and then withdrew it. When a man asks me what this is, what should I answer?

If you want to reply to this man, you can tell him that you have nothing important, or say in a relaxed tone, "Nothing, it's just that my hand slipped and I sent the wrong message." This can reduce embarrassment and show your sense of humor.

If you want to continue to communicate with him, you can change the topic or ask him if he has any hobbies. It is an important step to establish contact and get to know each other gradually in chat.

However, if you don't want to talk to him, you can simply say that you don't want to talk, or you are busy now and have time to talk again. It is important to respect your feelings and needs and not be forced to communicate with people who are not interested.