breaking off an engagement
Refers to the act of calling off a marriage engagement, often with legal or social implications.
He unilaterally announced the breaking off of the engagement.
She was sued for compensation for breaking off the engagement.
婚約 means 'engagement' (the promise to marry), while 婚約破棄 is the act of breaking that promise.
破棄 means 'cancellation' or 'annulment' in general, but 婚約破棄 specifically refers to engagement cancellation.
Compound of 婚約 (engagement) and 破棄 (cancellation, annulment).