Doctor Repellent is a term used to describe a type of insecticide that is designed to repel insects, such as mosquitoes, from entering a home or other area. It is often used in areas where there is a high risk of mosquito-borne diseases, such as malaria. The term 'Doctor Repellent' comes from the fact that it is designed to keep doctors away from the area, as they are more likely to be exposed to the disease. The crossword solution for this term is APPLE, which is a reference to the fact that many types of apples contain natural insect repellents.