a chink in armour: o que isso significa?

You know in a classroom there are many kinds of students right? A particular kind maybe has to do with what we're talking about today. Imagine there's this classmate of yours that's very intelligent. There's only one problem though: he is extremely lazy. You've never met anyone as lazy as him in your entire life. But despite of his laziness, he can get good grades because he can count on his intelligence that works regardless of how lazy he is. So you think how better could he be if he stopped being lazy and started taking things seriously. How far would he go? So you talk to him and say: I know you're intelligent, but your laziness is the chink in your armour. When you say something is the chink in their armour, that means that thing is a small fault that can cause them problems. In the case of your friend, being lazy may be the chink in his armour because in the future he might pass up many opportunities that would lead him to become a very successful person. And that's all for today. Take care!