to show that you think someone or something is stupid

I can't go into work looking like this - everyone will laugh at me. 我不能这个样子去上班——大家会笑话我的。

to treat someone or something as if he, she, or it is not important or does not deserve serious attention

If you say that, people will just laugh at you. 如果你那样说，人们就会看不起你。