hacky sack
See also: hackysack and Hacky-Sack
English
Etymology
A trademark of Wham-O. It uses reduplication of the word sack with the word hacky; a "hack", in the game's terminology, is akin to a point, and happens when every player in a group successfully passes the footbag.
Noun
hacky sack (countable and uncountable, plural hacky sacks)
- (uncountable, games) A game or activity in which one or a group of players try to keep a footbag off the ground using only the feet.
- (countable) The footbag used for such a game.