Code Of Arms

Trained to only kill other armed warriors, you hesitate when attacking unarmed opponents.
Prerequisite: Good or lawful alignment.
Effect: You suffer a -4 penalty on attack rolls made against an enemy not armed with a melee weapon. If the enemy uses a natural attack against you, you may then attack it without penalty.
Suggested Class/Race: Paladins
Source: Dragon Magazine #324 (Class Acts - Flaws For Paladins)