go back on — not do something you promised or agreed to do
phrasal verbB2IELTS 5.5+neutralcommon
to break a promise or agreement; to decide not to do something you said you would do.
Say it like a native
Textbook He failed to honour his commitment.
Native He went back on his word.
'Go back on (your word/promise)' is the idiomatic phrase. 'Failed to honour his commitment' is formal/legal.
Pattern: go back on + (one's) word/promise/agreement
In use
- He promised to help me move, but then he went back on his word at the last minute.relationships
- In my opinion, it's important not to go back on your promises, especially when working in a team.IELTS speaking
Common mistake
✗ Don't go back your promise.
✓ Don't go back on your promise.
Needs 'on' — 'go back ON a promise / your word / the deal'.
Common collocations
go back on + commitment— your word, a promise, the deal, an agreement
Don't confuse it
'Go back to' means to return to a place or situation, not to break a promise.