To break a promise
Example: She broke a promise yesterday.
Definition
"To break a promise" means to fail to do something that one has assured or committed to do. It involves not keeping one's word or going back on a commitment made to another person, often resulting in disappointment or loss of trust.
Etymology
The phrase "to break a promise" combines the verb "break," originally meaning to separate into pieces, with "promise," from Latin 'promissum,' meaning a pledge or assurance. The metaphorical use of "break" evolved to signify violating or failing to uphold an agreement.