A veer screen is a ball screen that is faked: the big steps up as if he is setting it. The handler takes one dribble toward it. Then the big turns and runs straight down into a pin-down for the shooter in the corner, and the ball screen never happens.
Why coaches use it
The threat is the point. One dribble at a ball screen is enough to make two defenders commit to the ball — the on-ball defender squares up to fight over it, and the big’s man steps up to hedge or to be in position to switch. Both of them are now looking at the ball.
Meanwhile the shooter’s defender is guarding an ordinary corner spot-up and has heard no call. The screen that arrives is one nobody warned him about.
Be aware of the naming. Some coaches use “veer” strictly for this action — a ball-screener veering into a pin-down. Others use it for the ball-screener veering into any off-ball screen at all. The read is the same either way, but say which one you mean when you install it.
How it is guarded
It is a communication problem before it is a technique problem. The big’s defender has to recognize that the screen is not coming and go with his man rather than stay with the ball.
For the shooter’s defender, the usual choices apply: chase him over the top and take the catch-and-shoot away, top-lock him so he cannot use the screen, or switch it and live with the size difference inside.
Draw it with a defense set to switch, then replay it with the same defense set to chase. The shot you give up moves from the corner to the rim.