also: smash concept · hi-lo corner
A short route underneath and a corner route over the top of the same defender, so he cannot cover both. The standard answer to a corner sitting on a flat zone.
One receiver runs a short route, usually a hitch, and another runs a corner route behind him on the same side. The two routes attack one defender at two depths, and the quarterback throws to whichever one that defender does not take.
It is aimed at a corner playing a zone with flat responsibility. If he sinks to carry the corner route, the hitch is open in front of him; if he squats on the hitch, the corner route is behind him. That is the whole concept and it is why smash is described as a high-low: it is not a pattern so much as a question posed to a single player.
Against man coverage it stops being a bind and becomes two individual routes, which is why smash is usually paired with a call or a tag that changes it when the offense reads man.
smash conceptflood, daggerSmash is a hi-lo concept, which is a category rather than a play: any two routes stacking a defender vertically are a high-low. Knowing the category is worth more than knowing smash, because it lets a coach recognize the same idea when the routes and the name both change.