Axe Master

You're a master of the axe and can move quickly when using it. The following benefits apply only to the use of handaxe , battleaxe, and greataxe.

• When you take the Attack action and attack with only a handaxe (melee), battleaxe, or greataxe, you can use a bonus action to make a melee attack with the flat edge of the weapon. This attack uses the same ability modifier as the primary attack. The weapon’s damage die for this attack is a d4, and it deals bludgeoning damage.
• When you roll a 1 or 2 on a damage die for an attack you make with an axe weapon that you are wielding, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2.

this feat does not grant proficiency with any weapons, it only applies to weapons you are already proficient with.