Dueling Master

In order to take this feat you must have the Dueling fighting style. You have become a master of fighting with a weapon in just one hand. 

When you take this feat you add a +1 to your AC when you have a weapon in one hand and nothing in/on the other hand/arm. (No Shield)

When you have this feat and have a weapon in one hand and nothing in the other hand and you use an action to make an attack with your weapon in one hand you can use a bonus action to make one additional attack with that weapon.