The term 'least sweet' can be described by three crossword solutions: DRYEST (6 letters), TARTEST (7 letters), and DRIEST (6 letters). DRYEST is an adjective that means having little or no moisture, while TARTEST is an adjective that means having a sharp, acidic taste. DRIEST is also an adjective that means having very little moisture. All three words describe the lack of sweetness in a food or beverage.