O que significa "Achilles' heel"?

Imagine you know a man of few words. He's always very calm and you're pretty sure even though you've known him for a long time, you've barely seen him get mad. Even in the most stressful situations, he's always giving people lessons on how to remain calm. But then somebody asks you: is there anything that upsets him? What's his weakness?

And here's your answer: If you want to make him mad, just mess with his kids. They are his Achilles' heel. But wait, Achilles' heel? What does that mean? If Achilles sounds familiar to you, that's because you may have heard of the story of a man in Greek mythology who was killed when he was injured on the heel. That was the only part of his body where he could be harmed. So when you talk about someone or something's Achilles' heel, you're referring to their weak point, a fault that might cause them to fail.

One of these days I read a headline that read something like this: Hacker found Apple's Achilles' heel. We all know how big and intimidating Apple is. When a hacker can finally find its weak point, it's like finding the only place in someone's body that can kill him once it's harmed. I hope that helped. Talk to you next time!