The most appropriate definition of the medical malpractice would be like:
Medical malpractice is an act or lapse committed by a medical professional or medical services providing agency such as a hospital, which moves away from established norms of medical practice in the community and causes injury or death to the patient. Or in more simple terms, medical malpractice is professional negligence or misconduct of a medical professional or group of professionals that causes an injury or death to the patient.