rat onsb/sth
—phrasal verbwithratverbslangdisapprovinguk/ræt/us/ræt/
to not beloyalto someone,especiallyby giving awaysecretinformationabout them, or tofailto do something that you said you would do
背叛；（尤指）告密出卖，对…背信弃义
He ratted on us.他出卖了我们。
They ratted on thedeal.他们不守信用，谈好的交易出尔反尔。