Picture a joint that was glued and is not holding any more. Nothing has been broken and nothing has been cut; the thing that was keeping the pieces together has simply let go, and now they slide apart on their own. Every use of this word is that moment — first with wood and paper, then with a plan, then with a person.
可以想成一個原本黏好的接縫，現在黏不住了。沒有人打破它，也沒有人切開它——只是那層把東西固定在一起的膠鬆開了，於是零件自己滑開。這個字的每一個用法，都是在講那一刻：先是木頭和紙，接著是一整套計畫，最後是一個人。所以它跟「壞掉」不一樣：壞掉是東西本身出問題，unglued 是「撐著它的那層東西放手了」。
From the word’s history
From un- + glued (Wiktionary). The prefix un- reverses the adjective, so the word literally says 'not glued any more'.
字典把它拆成 un-（解除、相反）加上 glued（黏住的）。字面就是「不再黏著」。這個拆法跟核心畫面完全吻合，也是為什麼比喻用法這麼好懂：讀者腦子裡本來就有那層膠。
Wiktionary entry for unglued: "From un- + glued." (etymology tree: un- < Old English un- ; glued < glue)
登入就可以看每一支怎麼連回核心畫面。