Kryptonite

Part of speech: noun

Pronunciation: /ˈkɹɪptənaɪt/

Definitions

1. A legendary material known for its ability to diminish the strength of a specific hero
2. a symbolic representation of an individual's or group's vulnerability
3. A mythical mineral that causes loss of power to a noted comic book hero ; a figurative term for something that severely weakens or undermines a person or group

Etymology: Kryptonite began as a plot device rather than a scientific term. In the Superman comics, it is a fictional radioactive substance from Krypton, the hero's home planet, and it is the one thing capable of weakening an otherwise invulnerable man. The name is built from "Krypton" plus the mineral-style suffix "-ite," a pattern borrowed from real rocks and minerals, and the planet's name itself comes from the chemical element krypton, which was named after the Greek "kryptos," meaning "hidden." The word's later sense grew out of that fictional role. Once a writer could hang a single fatal vulnerability on a hero, the term became a handy metaphor, so that anyone's critical weakness, whether a food, a habit, or a person, can be described as their kryptonite. The figurative use is now more common than the comic-book origin that produced it.