Defensive Duelist
Prerequisite: Dexterity 13 or higher
When You are Wielding a Finesse Weapon with which You are Proficient and another Creature Hits You with a Melee Attack, You can use your Reaction to Add your Proficiency Bonus to your AC for that Attack, potentially causing the Attack to miss You.
Comments
Author's Notes
Original Article for The Players Handbook D&D 5E by Wizards of the Coast (WoTc)