A hit-and-run is when someone causes an accident and then leaves the scene without stopping to help or take responsibility. The term comes most often from car accidents: a driver hits another vehicle, a person, or property like a mailbox, then drives away instead of staying to exchange information or call for help. This is illegal because people who are hurt may need assistance, and everyone involved needs to know what happened.

The phrase also describes other situations where someone does something harmful and quickly disappears. In baseball, a hit-and-run play happens when a runner starts sprinting toward the next base just as the batter swings, trying to advance before the ball arrives. In military terms, hit-and-run tactics involve quick attacks followed by rapid retreats.

What makes something a hit-and-run is the combination of action and escape. The person doesn't stick around to face consequences or help fix the problem they created. A student who breaks something and walks away before anyone notices is attempting a hit-and-run. In contrast, someone who accidentally breaks a window but immediately tells an adult and offers to help repair it is taking responsibility, which is the opposite of hit-and-run behavior.