You have done extra training and become a specialist in a specific type of weapon.

Pommels: Greatsword, Longsword, Rapier, Scimitar, Shortsword

You must be proficient with the weapon you are using to gain the benefits listed below, and you must be proficient with at least one weapon in the group listed above in order to take this feat.

• When you take the Attack action and attack with one of the weapons listed above, you can use a bonus action to make a melee attack with the opposite end 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. 
• Go for the Nose! When you hit a target with a bonus action attack as described above, you can force the target to make a Constitution Saving Throw against a DC equal to 8 + your Strength modifier + your Proficiency Bonus. On a failed save, the target is stunned until the end of their next turn. You may use this feature a number of times per day equal to your proficiency modifier.