Powerful Attacker A5E
You gain proficiency with the Cleaving Swing maneuver and do not have to spend exertion to activate it. In addition, you can use Cleaving Swing with a versatile weapon wielded with two hands.
Before you make a melee attack with a two-handed weapon or versatile weapon wielded with two hands, if you are proficient with the weapon and do not have disadvantage you can declare a powerful attack. A powerful attack has disadvantage, but on a hit deals 10 extra damage.
Source: Adventurer's Guide (EN Publishing) · License: Creative Commons Attribution 4.0 / OPEN GAME LICENSE Version 1.0a details