In law, behaviour that contributes to one's own injury or loss and fails to meet the standard of prudence that one should observe for one's own good.
Contributory negligence of the plaintiff is frequently pleaded in defense to a charge of negligence . In Engish law and in the law of many U.S. states, if the plaintiff is shown to have contributed through negligence to his own injury, recovery may still be allowed, but provision is made for an equitable reduction of damages. Contributory negligence has been criticized by some authorities because it effectively excuses one party (the defendant) even though both were negligent.