Meaning of the word "go back on one's word" in English

What does "go back on one's word" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

go back on one's word

US /ɡoʊ bæk ɑn wʌnz wɜrd/
UK /ɡəʊ bæk ɒn wʌnz wɜːd/

Idiom

to fail to keep a promise or agreement

Example:
He promised to help me, but then he went back on his word.
A good leader never goes back on their word.