Better Lucky than Good (3.5e Feat)
From D&D Wiki
 Better Lucky than Good [General]
You've never been the best, but that hasn't stopped you from having an uncanny amount of success.
Prerequisite: Positive Charisma modifier.
Benefit: A character who selects this feat uses his Charisma modifier in place of his Dexterity modifier for determining his Armor Class.
Normal: A character without this feat adds his Dexterity modifier to his Armor Class.
Special: This feat may only be selected a first level. A character who has this feat is still subject to Armor Check penalties for Dexterity-based skills. An armor's Maximum Dexterity Bonus still limits the character's Dexterity. The only aspect in which the Charisma modifier replaces the Dexterity is for Armor Class.