What does the term hacky sack mean?

"Hacky sack" is a slang term for a footbag, a small beanbag-like object that is kicked, juggled, and passed around with the feet, head, and other body parts.

The term "hacky sack" is believed to have originated in the 1970s, likely from the way players would "hack" at the bag with their feet. It became a popular pastime in the 1980s and 1990s, especially among young people.

Today, "hacky sack" is still used as a casual term for the game and the object itself, although "footbag" is considered the more formal name.