If something is kaput, it is broken — finished, no longer working. People say it about machines first: a car, a phone, a washing machine that has given up. They also stretch it a little: a plan can be kaput, a friendship can be kaput, meaning it is over. The word is informal and a bit jokey. It has a German flavour, and it sounds slightly old-fashioned in some places — though actually, English speakers still use it when they want a short, almost comic “it’s dead.” You would not put it in a careful school essay or a formal letter. Younger speakers might say busted, broken, or dead instead. Grammar stays simple: something is kaput. We do not really say kaputted.

壞掉了；完蛋了（口語，帶點俏皮、德語味道）