Blitz
A defensive rush sending more players than usual after the quarterback.
On a blitz, the defense sends extra players — usually linebackers or safeties — to rush the quarterback, beyond the standard four-man rush. The goal is to shrink the time the quarterback has to decide where to throw.
The risk is real: every player sent on a blitz leaves a zone uncovered behind them, which a prepared offense can exploit with a quick pass. That's why blitzes are used most often on long-distance downs, where a short pass into that zone is less likely to convert anyway.
Defensive coordinators are known and praised for their ability to disguise a blitz until the last second before the snap, denying the offense time to adjust protection.