sever
To cut something completely apart, or end a connection fully.
To sever means to cut through something completely, separating it into pieces. A lumberjack severs a tree branch with an axe. A surgeon might sever a damaged nerve during an operation. The word suggests a clean, decisive cut rather than a partial tear or gentle separation.
The word also describes ending a connection or relationship completely. When a company severs ties with a dishonest supplier, they cut off all business dealings. Friends might sever their friendship after a serious betrayal. Countries sometimes sever diplomatic relations, meaning they stop communicating officially and close their embassies.
Notice how sever implies finality. You don't sever something you plan to reconnect easily. When a rope is severed, the two pieces fall apart. When a partnership is severed, both sides go their separate ways. The word carries weight because it describes breaks that are meant to last.
Severance is the noun form. An employee who loses their job might receive severance pay to help them during the transition. The related word severe looks similar but means something different: extremely serious or harsh, like severe weather or a severe storm.