Overview
A powerbomb is a professional wrestling throw in which an opponent is lifted (usually so that they are sitting on the wrestler's shoulders) and then slammed back-first down to the mat. The standard powerbomb sees an opponent first placed in a standing headscissors position (bent forward with their head placed between the attacking wrestler's thighs). The opponent is then lifted on the wrestler's shoulders and slammed down back-first to the mat. A prawn hold is commonly used for a pinning powerbomb.
Powerbombs are sometimes used in mixed martial arts competitions, when a fighter attempts to slam another fighter who has him trapped in a triangle choke. In professional wrestling, it is also sometimes used by a bigger wrestler as a counter to an attempted hurricanrana by a smaller wrestler. While it was associated with super-heavyweight wrestlers, the move was invented by Lou Thesz.
Variations
Argentine powerbomb
The wrestler first places their opponent face-up across their shoulders, as in an Argentine backbreaker rack, hooks the head with one hand and a leg with the other, and the wrestler will then spin the opponent's head away from them, dropping the opponent down to the mat. Often the wrestler drops to a seated position while spinning the opponent. Innovated by Lioness Asuka, who called it the Towerhacker Bomb and popularized by AJ Styles as the Rack Bomb.
From Wikipedia (CC BY-SA 4.0).