vector shield

There was the sound of bones breaking behind Accelerator.
Of course, they didn’t belong to him. They belonged to the scoundrel who tried to stab
him in the back with his knife. His wrist was broken. The force vector of all his body weight
behind the knife had been reflected...and his slender wrist couldn’t endure the strength
of the rest of his body.

- Toaru Majutsu no Index Volume 5, Chapter 1 Part 1