You have either learned to fight (or not) in styles which do not mesh well with certain weapons, or else you find those weapons clumsy and awkward. Choose a style of weapon: blades, bludgeons, guns, bows, exotics, polearms, axes, etc. You take a −4 penalty to Attack and parry rolls when using that sort of weapon. You can take this Fault multiple times. Each time, it applies to a different weapon category.