Windshear

Windshear is a unique sword found in The Elder Scrolls V: Skyrim. Although its appearance is identical to the Scimitar, the enchantment is one of a kind and cannot be disenchanted.

Acquisition
This sword can be located during the Dark Brotherhood quest Hail Sithis!, on a ship called The Katariah. This ship can only be accessed during or after the quest.

Proceed onto the main deck of the boat. Follow the stairs that lead to the bow (the front of the ship). Here you will notice a long wooden beam protruding from the bow (Bowsprit). Carefully walk up the beam to the top and you will see the Windshear wedged into the wood.

Enchantment
The enchantment of Windshear is described as "Bash attacks made with this weapon have a chance of knocking enemies down". In combat, this effect is actually much more powerful as rather than chance, every attack will stagger all enemies 100% of the time. This makes Windshear a very formidable weapon.

Bugs

 * There may be a bug where the weapons spawns under the forward mast hovering in mid air making the weapon difficult if impossible to aquire normally. One can, however, simply shoot this down into the water below for retrieval using an arrow or a destruction spell. Tested on the Xbox 360 and the Playstation 3 versions.
 * This weapon also seems to get "stuck" in your hand when unequipped. This can be fixed by unequipping and reequipping any gloves/gauntlets.