Each weapon has a mastery property, which is usable only by a character who has a feature, such as Weapon Mastery, that unlocks the property for the character.

List of Mastery Properties

Official
NameSource
NickPlayer’s Handbook (5.5e)
PushPlayer’s Handbook (5.5e)
SapPlayer’s Handbook (5.5e)
SlowPlayer’s Handbook (5.5e)
TopplePlayer’s Handbook (5.5e)
VexPlayer’s Handbook (5.5e)
Third Party
NameSourcePublisher