Achilles heel意思

"Achilles heel" is an English idiom that comes from Greek mythology. In the story of the Trojan War, Achilles was a Greek warrior who was nearly invincible. He was said to have been dipped into the River Styx as a baby, which made him invulnerable to harm in all parts of his body that the water touched. However, his heel, where he was held by his ankle, was left vulnerable.

The phrase "Achilles heel" is used to describe a weakness or a vulnerable spot in someone or something that is otherwise very strong or invincible. It suggests that even the most powerful or invulnerable person or thing has a weakness that can be exploited.