severance
A complete and often permanent separation or ending of something.
Severance is the act of cutting or separating something completely, creating a clean break between things that were once connected. When a rope is cut in two, that's a severance of the rope. When a friendship ends abruptly, you might describe it as a severance of the relationship.
The word appears most often in the phrase severance pay (or a severance package), which is money a company pays an employee when their job ends. This payment helps bridge the gap while the person looks for new work. For example, if a company closes a division and lets 50 workers go, it might offer each person three months of severance pay to help them during the transition.
Severance implies a complete and often permanent separation. It's more final than a pause or temporary break. When surgeons sever a nerve, they're cutting it entirely. When diplomats talk about the severance of relations between countries, they mean those countries have stopped communicating and working together, at least for now.