The crossword solution for the term LEAST DAFFY is SANEST, which is a six-letter word. The term LEAST DAFFY is an adjective that means having the least amount of silliness or foolishness. The word SANEST is also an adjective that means having the most amount of soundness or wisdom. Therefore, the crossword solutions for the term LEAST DAFFY is SANEST, which means having the most amount of soundness or wisdom.