1. adjective (used before the noun) Guilty of causing a motor-vehicle accident and fleeing the scene so as not to be identified and held responsible. Police are appealing for witnesses to help identify the hit-and-run driver of this morning's fatal accident.

2. adjective (used before the noun) Of, involving, or resulting from a traffic accident in which the person responsible has fled the scene. This one intersection has seen more hit-and-run fatalities than the rest of the state combined.

3. adjective (used before the noun) Involving or relying on swift, effective action followed by rapid departure. There have been more hit-and-run attacks on military bases this month, as dissidents continue to intensify their guerrilla warfare tactics.

4. adjective (used before the noun) In baseball, of, involving, or denoting a play in which a base runner leaves for the next base as soon as the ball is pitched to the batter. The runner managed to steal third base as the ball rocketed down midfield in a beautiful hit-and-run maneuver.

5. noun (not always hyphenated) The act of causing or contributing to a motor-vehicle accident on the road and fleeing the scene so as not to be identified and held responsible. Luckily, a more concentrated police presence near busy intersections has cut down on the number of hit-and-runs over the past two years. No, officer, he left the scene—it was a hit and run!

6. verb (not always hyphenated) To cause or contribute to a hit-and-run. Some jerk decided to hit-and-run our parked car. Our insurance will cover it, but our premium is sure to go up! Using security camera footage, police were able to identify the driver who hit and ran an elderly couple late last night.

7. verb (not always hyphenated) In baseball, to attempt or execute a hit-and-run play. The score was deadlocked the entire game, but when one player hit-and-ran in the last inning she was able to set up the winning run.