Jinxes are usually spells whose effects are irritating but amusing. Hexes are considered slightly worse than jinxes, but are still only dark magic of a minor sort. Curses are usually the worst kinds of dark magic.
Behind the scenes
- Despite Rowling's descriptions of what classifies curses, hexes, and jinxes, there seems to be some inconsistency with which spells fall under each category. For example, the effects of the Leg-Locker Curse, Jelly-Legs Curse and Full Body-Bind Curse, which don't cause any lasting injury, seem to fall more under the definition of a jinx or hex, while Voldemort's Jinx on the post of Defence Against the Dark Arts teacher has had serious, lasting consequences for several of those affected, thus categorising it as a curse.