What is the origin of the idiom "chink in one's armor" and when to use it?

The idiom "chink in one's armor" has historical origins and refers to a small opening or crack in a suit of armor, which could leave a warrior vulnerable to attack. In the context of the idiom, it means a weakness or vulnerability that can be exploited by an opponent or enemy. The usage of the idiom has since expanded beyond its historical context and can now refer to any situation where someone has a weakness or vulnerability that could be exploited or used against them.