Answer: Slang for U.S. Country-Folk

In the early part of the 20th century, there was still a significant divide between the lifestyles of people living in U.S. cities and rural towns. Many regions of the country still didn’t have electricity, indoor plumbing, or widespread use of automobiles. In the Midwestern and Eastern United States, city-dwellers took to using the pejorative term “jay” to refer to country-folk that were unacquainted with life in the big city and often made mistakes or looked foolish as a result.

Although the use of “jay” to mean a silly or stupid person has vanished from common use in English, it has lived on in one particular way: jaywalking. Those country-folk, upon visiting the city, would rarely pay attention to fast-moving automotive traffic as there wasn’t any in their towns of origin. As a result, they’d often cross streets away from intersections and “jaywalk” their way into accidents.