Breakdown
Rupture
noun, verbal noun
The decision is split, causing a breakdown in all we've decided. A big ol' rupture.
決裂 is a formal word used when talks or relationships totally fall apart. Since it refers to a full-on rupture and sounds dramatic, you'll often see it in news headlines or news reports when negotiations between companies or countries crash and burn.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
両者の意見が合わず、話し合いは決裂した。
The two sides couldn't agree and the talks broke down.
交渉が決裂した原因は何だと思いますか？
What do you think was the cause of the breakdown in the negotiations?
合意目前での決裂は株式市場に大きな影響を与えました。
The collapse of talks on the verge of an agreement had a significant impact on the stock market.
あの男は奴らの決裂を、牢屋の中で舌なめずりをしながら待っていたに違いない。
That man was, no doubt, eagerly awaiting the breakdown of their relationship from within his jail cell.