Dereliction means abandoning or neglecting. In the context of the law, dereliction of duty can be charged against a person. This is a common charge in the United States Military. Dereliction of duty means that a person, typically a soldier or military personnel, had an obligation to perform a duty, and he or she deliberately abandoned that responsibility and did not perform the duty.
Dereliction can also be a relevant issue in negligence cases. For example, if a personal injury occurred as the result of a person's dereliction of duty, then the person who failed to perform his or her duty could be held liable for the injury. This could mean that he or she could be forced to pay damages if he or she loses the lawsuit. Dereliction can also refer to the abandonment of a ship (if the ship suddenly loses its seaworthiness).