The term 'Poppy-Based Narcotic' refers to a type of drug derived from the OPIUM poppy plant. The most commonly known example of this type of narcotic is OPIUM, which is a five-letter word that can be used to solve the crossword puzzle. OPIUM has been used for centuries as a pain reliever and sedative, and it is still used today in some parts of the world. It is also the source of many other drugs, such as morphine, codeine, and heroin.