A curse was a powerful magical effect placed upon a person, place, or object. Curses could have a wide variety effects, but were generally negative or harmful; they often involved weakening, injuring, or thwarting the intentions of an afflicted individual or by destabilizing an afflicted item. Minor curses were sometimes called "hexes", and typically lasted much shorter durations than a true curse.
In general, a curse was hard to remove, and only a handful of specialized Spells could hope to remove even a hex before they naturally broke. Stronger types of curses needed great power to remove, and some were not possible to remove with any earthly power.