人：用到沒電
把核心畫面放在人身上：不是想睡，是今天的力氣已經用完了。
adjective · B2
So tired that you have no energy left at all, usually after a long day or a lot of physical work.
累壞了
核心畫面
Something that has been used right to the end of what it had. The old word behind it points at the knacker's yard, the place worn-out working animals were sent when they could not work any more. Hold that picture and both uses fall out of it: a person with nothing left in the tank at the end of a long day, and a bike or a washing machine that has simply finished.
可以想成一樣東西被用到最後一點都不剩。這個字背後指向的是 knacker's yard——以前把已經做不動的老牲口送…更多收起
可以想成一樣東西被用到最後一點都不剩。這個字背後指向的是 knacker's yard——以前把已經做不動的老牲口送去、不再使用的地方。抓住那個畫面，兩個用法就都跟著出來了：一個人忙完一整天，身上什麼都不剩；一台腳踏車或洗衣機，也走到了它的盡頭。From the word’s history
From the verb knacker; the adjective is also traced to the phrases ready for the knacker's yard and fit to be knackered, said of worn-out livestock.
來自動詞 knacker；來源也把它接到 ready for the knacker's yard、fit to be knackered 這些說法，原本講的是已經做不動的牲口。
Wiktionary entries for knackered (kaikki:3f6f69a190036ae4:529380542 and :529390325), etymology sections supplied in the evidence packet
Two branches
東西：走到盡頭
同一個畫面換成機器和物品，重點一樣是「已經到底了」，不是「出了一次問題」。
adjective · C1
A machine or object that is knackered is so old or so damaged that it does not work any more.
壞到不能用