Nonproficient

If a character who is nonproficient in a piece of equipment has not been trained to use it. They take certain penalties until the appropriate proficiency Feat is taken.

Weapons

A character who lacks proficiency with a weapon she is using takes a -4 to both attack and damage when using that weapon. This also applies to counter rolls and similar checks, such as trip checks using the weapon to trip.

Weapon Feats, such as Weapon Finesse, Hack and Slash, and Far Shot may not be used with a weapon with which you are not proficient - you simply have no idea how to apply these skills to this weapon. This also applies to class or track abilities.

Armor and Shields

A character who wears armor and/or uses a shield with which she is not proficient takes the armor’s (and/or shield’s) armor check penalty on attack rolls and on all Strength-based and Dexterity-based ability and skill checks. Like normal, this stacks with everything.

A character using a not proficient shield cannot block projectiles with a shield check.

Proficiency for shield bashes is determined by martial weapon proficiency.