Defensive Duellist is a Reaction obtainable by a Feat of the same name. If you are attacked while wielding a Finesse Weapon weapon, you can temporarily increases your 
Armour Class.
Description
When attacked with a melee attack, add your Proficiency Bonus to your Armour Class, possibly causing attacks to miss.
Requires a Finesse Weapon you are Proficient in.
Properties
- Cost:
-
Reaction - Details:
-
Recharge: Per turn
How to learn
Granted by feats: Defensive Duellist (Feat)