Knockback
The shove that throws a character backward when hit — in some games the actual win condition rather than a side effect.
When an attack lands, subtracting health is rarely enough; the hit also has to feel like one. Knockback is the displacement the attack pushes its victim with, and unlike a physical impulse it is seldom derived from mass and velocity — it is hand-tuned per move, so a light kick and a heavy hammer throw a target different distances.
Super Smash Bros. turned knockback into the core mechanic: there is no health bar, instead a rising damage percent increases how far each hit throws you, until an opponent flies off the stage. Knockback is almost always paired with a short stun and with invincibility frames while the victim recovers.