Definition of boggle in the Idioms Dictionary. boggle phrase. What does boggle expression mean? Definitions by the largest Idiom Dictionary. Boggle is a word game designed by Allan Turoff and originally distributed by Parker Brothers. The game is played using a plastic grid of lettered dice, in which Players : 2+. boggle meaning, definition, what is boggle: to (cause something or someone to) have difficulty imagining or understanding something. Learn more.