No, we're talking not about a electric/compressed air driven tool. This is something like a fat, massive, screwdriver that you whack with a heavy hammer. This not only makes it turn a little, but also momentarily takes the pulling force from the screw (a screw works by pulling its head toward the thread).
As I'm sure a lot of this is lost in my translation, I'll link a pic:
Cheers, Remi
P.S.: If you don't have an impact driver, it may also help to hit on an ordinary screwdriver for the reason described above.
