go back on1.■食言，毁约，违约：He said he would loan money to us, and then went back on his promise.他说他会借钱给我们，后来他食言了。2.■出卖；背叛：Some of his friends have gone back on him.他有几个朋友对他不忠。3.■使失望；失去作用：Grandfather's eyes are going back on him.祖父的视力在减退。4.■[美国口语]5.■对…不忠实，背叛6.■食言，不遵守，不履行