Type: Weapon Group
Source: Unearthed Arcana
You understand how to use the exotic weapons associated with the weapon groups that you have mastered.
Prerequisite: Base attack bonus +1.
Benefit: When you take this feat, you gain proficiency in the exotic weapons associated with the weapon groups that you already know how to use. Whenever you take a Weapon Group proficiency feat, you also gain proficiency in the exotic weapons (but not the exotic double weapons) associated with that group.
Axes: dwarven waraxe (one-handed use).
Bows: elven double bow, greatbow, composite greatbow.
Claw Weapons: bladed gauntlet, claw bracer, panther claw, stump knife, tiger claws, ward cestus
Clubs and Maces: warmace (one-handed use), tonfa.
Crossbows: great crossbow, hand crossbow.
Druid Weapons: greatspear.
Flails and Chains: chain-and-dagger, scourge, spiked chain, three-section staff, whip, whip-dagger.
Heavy Blades: bastard sword (one-handed use), khopesh, mercurial longsword, mercurial grearsword.
Light Blades: kukri, sapara5, triple dagger, war fan.
Monk Weapons: butterfly sword, tonfa.
Picks and Hammers: dire pick, gnome battlepick, maul (one-handed use).
Polearms: heavy poleaxe.
Slings and Thrown Weapons: bolas, chakram, gnome calculus, halfling skiprock, orc shotput, shuriken, throwing iron.
Spears and Lances: duom, greatspear, harpoon, manti spinning javelin.
Special: If you include exotic weapons from sources other than the Player's Handbook book, the DM should feel free to assign those weapons to a weapon group as appropriate for the campaign.
Normal: When using a weapon with which you are not proficient, you take a -4 penalty on attack rolls.