Proficiency

Proficiency indicates a character's familiarity and training with specific equipment, and applies to Weapons, Armor, and Shields. These types of equipment all have a Proficiency Rank: 1 to 4 for Weapons, 1 to 8 for Armor, and 1 to 3 for Shields. Generally speaking, higher Ranks indicate a higher level of training or experience required to use them.

Proficiency can be granted by Classes, Races, and some Feats. You can be granted proficiency in all items of a specific rank (such as Rank 3 Armors), in a group of items of a specific rank (such as Blades), or for a specific item (such as a Rapier). When you are granted proficiency in items of a specific rank (and/or a specific group and rank), you are also granted proficiency for any items of lower rank (and within the same group, if applicable).

Using Weapons, Armor, or Shields Without Proficiency

If you attempt wield a Weapon you are not proficient with, it is considered a Improvised Weapon (small if Off-Hand, medium if One-Hand, or large if Two-Hand). If you attempt to wield Armor or a Shield you are not proficient with, you suffer a penalty to attack rolls equal to the Check Penalty of the Armor or Shield.