Snake oil, supposedly, is a term used to describe fraudulent products or services that are falsely advertised as having miraculous healing powers. The term originated in the 19th century when traveling salesmen would sell a concoction of mineral oil and other ingredients as a CURE-all remedy. It has since become a metaphor for any product or service that is falsely advertised as being able to solve all problems. The crossword solution for this term is 'CURE', which is a four letter word.