To move as fast as possible. Hell in this expression dates from the nineteenth century and simply implies very fast (as in “to go like hell”); the origin of leather, however, is no longer known. The most common citation is Rudyard Kipling’s poem “Shillin’ a Day” (1892): “When we rode Hell-for-leather, Both squadrons together.” The variant, hellbent, means stubbornly determined (or “bent on going to hell”) as well as very fast, and is an early nineteenth-century Americanism. Sue MacVeigh used it in her 1940 murder mystery, Streamlined Murder: “It was going hell-bent for election.”