From Longman Dictionary of Contemporary Englishgo back on something phrasal verbPROMISEto not do something that you promised or agreed to dogo back on your word/promise/decision Delors claimed that the president had gone back on his word. → go→ See Verb table
Examples from the Corpus
go back on • What if the dealer had a cash-in-hand offer from some one else and went back on his word?• Dagenham workers were angry that Ford had gone back on its promise to build the new Fiesta in Essex.go back on your word/promise/decision• But he promised to serve for only one term, and refuses to go back on his word.• Gerry: But the Union can not now afford to go back on its decisions.• Now he had the nerve to go back on his word.• What if the dealer had a cash-in-hand offer from some one else and went back on his word?• When the item is starting to hang together and the class is settling dow, don't go back on your decisions.• You haven't gone back on your promise, have you?• Dagenham workers were angry that Ford had gone back on its promise to build the new Fiesta in Essex.• He accused the Labour group of going back on its promise to look after the interests of the handicapped.From Longman Business Dictionarygo back on something phrasal verb go back on your promise/word to break a promiseYou can rely on her. She won’t go back on her word. → go→ See Verb table 