The four crossword solutions for the term 'insect repellent ingredient' are Aloe (4 letters), DEET (4 letters), DEE (3 letters), and OrangeOil (9 letters). Aloe is a plant extract that has been used for centuries as a natural insect repellent. DEET is a chemical compound developed in the 1940s and is one of the most widely used insect repellents today. DEE is an acronym for diethyltoluamide, which is the active ingredient in many insect repellents. OrangeOil is an essential oil derived from orange peels that has been found to be effective against certain insects.