Hardhead
Explorer
Welcome to post-EverQuest roleplaying. That's where terms such as "broken" and "game balance" came from. I never heard these things in previous editions of the game.
The poster above is correct. Magic: The Gathering originated the term "broken."
Since Magic cards are practiaclly the "rules" of that game, when a card that was way overpowered came out, it would "break" the game enviornment, thus the term "broken" came about.
The reason it's become so popular is because it's such a useful word. It fills a niche no other word does. Something may be "overpowered" or "unbalanced," but is it actually so bad it causes the game to "break" in terms of game balance? Is it so bad that the game cannot function correctly with it's inclusion? If so, then it's broken.
I really like the word. It serves a real purpose (as most new words do that become popular - that's often how they enter the language). It allows me to quickly let someone else know exactly how overpowered something is without spending a paragraph explaining my pure and undying fear/hatred of a spell/feat/race/whatever, and let me spend my time explaining why I don't like it instead of how much I don't like it.