Knockback

From Diablo Wiki

Knockback is a Special Modifier. If a weapon or item has the Knockback modifier any hits that you land upon a target will knock the target back a certain distance. The distance is set so multiple knockback modifiers have no effect. You must actually hit a target to knock it back, missing will do nothing.

Special Modifiers
Absorption • Crushing Blow • Deadly Strike • Demon Heal • Defense vs. Missiles • Ignores Target's Defense • Increased Blocking Speed • Knockback • Open Wounds • Piercing • Slows Target