An abnormal condition of a part, organ, or system of an organism resulting from various causes, such as infection, inflammation, environmental factors, or genetic defect, and characterized by an identifiable group of signs, symptoms, or both, an impairment of health or a condition of abnormal functioning, verb_ To infect with a disease, obsolete To cause unease; to annoy, irritate, transitive verb_ obsolete To deprive of ease; to disquiet; to trouble; to distress, To derange the vital functions of; to afflict with disease or sickness; to disorder; -- used almost exclusively in the participle diseased