noun
footbag; hacky sack
A small beanbag-like ball used in the game of footbag, where players keep it in the air using their feet. Hacky Sack is a common brand name often used generically.
公園で友達とフットバッグをして遊んだ。
I played footbag with my friends at the park.
彼はフットバッグの技を練習している。
He is practicing footbag tricks.