You must be smarter than the grass you walk on. Share definition Flag Phrase used to encourage football players. First used by Mr. Tim Treder's coach. "Tim you must be smarter than the grass you walk on." You must be smarter than the grass you walk on. by Set 9 Weightlifting February 6, 2008 0 0 Get merch Get the You must be smarter than the grass you walk on. mug. Buy Now — $32.95 See more merch