There are many examples of this scenario, both in fact and fiction; an untranslatable word so laden with connotation that it cannot effectively be replaced. Usually, these words represent some core value of their society of origin (reference: the Dwarves' Super-Honor in Eragon). In a way, the fact that they cannot be translated helps convey their meaning, showing their importance and giving them a quality of both simpleness and complexity, as if your brain was meant to have a word for them, as if they were simply a basic part of the universe falling into place. It's a beautiful thing, really.