We have all heard the phrase Achilles Heel, referring to the critical mistake or flaw in a plan, or a weak part of something, especially of someone’s character, which is easy for other people to attack.
What exactly is the origin of this phrase and who, pray tell, be this Achilles chap? Well, that’s because the origins of this one are old—from Greek mythology, so well over two thousand years old. Achilles was literally invulnerable apart from the heel that he was held by when his mother made him immortal by dipping him in the Styx.
So anyhow the only part that was vulnerable was his heel, and the phrase has stuck around ever since as any small but fatal flaw in a plan being known as its Achilles Heel.
Achilles Heel 阿喀琉斯之踵（阿喀琉斯的脚踵），喻指“致命的弱点，致命伤”。希腊神话中的阿喀琉斯出生后被其母亲手握脚踵倒提着在冥河水中浸过，因此除未浸倒水的脚踵外，浑身刀枪不入
chap 〈口〉家伙，小伙子
dip 浸
immortal 不死的，长生的
invulnerable 不能被伤害的，刀枪不入的。下文出现的vulnerable是其反义词，意思是“易受伤的”
mythology 神话
Styx 【希神】（环绕冥土四周的）冥河