Knights are more about finesse and grace in combat than raw, knock-down power.
Those trained with such smashing weapons as the mace or the flail would rather
score a light hit on a vulnerable spot than risk overextending themselves,
leaving them open to a counterattack. This skill lets a knight use any
one-handed bashing weapon to try to cave in the skull of their target. Skill
with the weapon used is a must, and lighter weapons are more accurate but
cause less damage.
Note that some weapons work better against some creatures than others. Arms lore may help.