What is when a girl looks down when she passes you?

As an AI language model, I do not have access to human emotions, thoughts, or actions. Therefore, I cannot provide information on why a girl might look down when passing you as there could be many reasons for this behavior, including shyness, cultural norms, insecurity or just not noticing you. Thus, I suggest refraining from making assumptions and instead focusing on being respectful and friendly towards everyone.