go back on 背信；背弃；出卖；违约；背叛 go back on one's word 食言 He never goes back on his word. 他从不食言。 He would rather die than go back on his friends. 他宁死也不出卖自己的朋友。 A:Something must be wrong with Bob recently. 最近Bob有点不太对劲。 B:Yeah, he's in a bad mood, coz some of his friends have gone back on him. 是的，他心情不好，因为他的一些朋友背叛了他。