In this sense, undoing is a noun meaning the cause of someone's ruin, downfall, or disgrace — the thing that destroys them. It lives almost entirely inside one pattern: "X was his undoing" or "X proved to be her undoing", and very often "his own X was his undoing".

In this sense在這個意思裡, undoing is a noun meaning the cause of someone's ruin, downfall, or disgraceundoing是名詞指造成某人毀滅、垮台或名譽掃地的原因 — the thing that destroys them那個把他們毀掉的東西。It lives almost entirely inside one pattern它幾乎只出現在一種固定句型裡: "X was his undoing"『X是他的致命傷』 or或 "X proved to be her undoing"『X結果成了她的致命傷』, and而 very often "his own X was his undoing"常常是『他自己的X就是他的致命傷』。

"His pride was his undoing." "Greed proved to be their undoing." "That one careless email was his undoing." There is nearly always a touch of irony, because the undoing is usually something that belonged to the person and once helped them — their confidence, their charm, their cleverness — which then turned round and finished them. That flavour of a fall you brought on yourself is the heart of the word, and it is why it appears so often in stories, court reports, and sports writing about a great player's last season.

"His pride was his undoing."『他的驕傲是他的致命傷。』"Greed proved to be their undoing."『貪婪結果成了他們的致命傷。』"That one careless email was his undoing."『那一封不小心的email就是他的致命傷。』There is nearly always a touch of irony幾乎總是帶點諷刺的味道, because因為 the undoing is usually something that belonged to the person and once helped them那個致命傷通常是這個人自己擁有、曾經幫過他的東西 — their confidence, their charm, their cleverness他的自信、他的魅力、他的聰明 — which then turned round and finished them後來反過來把他毀了。That flavour of a fall you brought on yourself那種自己害自己跌倒的味道 is the heart of the word正是這個字的核心, and而 it is why it appears so often in stories, court reports, and sports writing about a great player's last season也是為什麼它常常出現在故事、法庭報導，還有寫一位偉大選手最後一季的體育報導裡。

It is a formal, slightly literary noun and a fixed phrase; "the undoing of" also works — "ambition was the undoing of the company".

It is a formal, slightly literary noun and a fixed phrase這是一個正式、帶點文學味的名詞，也是固定用法; "the undoing of" also works『the undoing of』也可以用 — "ambition was the undoing of the company"『野心就是這家公司的致命傷』。

Do not confuse it with the ordinary -ing form of the verb undo, which is much more common and quite different: undoing your shoelaces, undoing a button, undoing the damage, undoing years of good work. Same spelling, everyday meaning, no ruin involved.

Do not confuse it with the ordinary -ing form of the verb undo不要跟動詞undo的一般-ing形式搞混, which is much more common and quite different那個用法常見得多、意思也完全不同: undoing your shoelaces解開你的鞋帶, undoing a button解開一顆鈕扣, undoing the damage彌補損害, undoing years of good work把多年的努力毀掉。Same spelling拼法一樣, everyday meaning但是日常意思, no ruin involved沒有涉及毀滅。