"hacky sack" meaning in English

{
  "etymology_text": "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.",
  "forms": [
    {
      "form": "hacky sacks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "hacky sack (countable and uncountable, plural hacky sacks)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Games",
          "orig": "en:Games",
          "parents": [
            "Recreation",
            "Human activity",
            "Human behaviour",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "_dis": "96 4",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "94 6",
          "kind": "other",
          "name": "English entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "91 9",
          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "86 14",
          "kind": "other",
          "name": "English genericized trademarks",
          "parents": [
            "Genericized trademarks",
            "Terms by etymology",
            "Trademarks",
            "Terms by usage"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "88 12",
          "kind": "other",
          "name": "English reduplications",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "92 8",
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "83 17",
          "kind": "topical",
          "langcode": "en",
          "name": "Sports",
          "orig": "en:Sports",
          "parents": [
            "Human activity",
            "Human behaviour",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "A game or activity in which one or a group of players try to keep a footbag off the ground using only the feet."
      ],
      "id": "en-hacky_sack-en-noun--tRJhekY",
      "links": [
        [
          "games",
          "game#Noun"
        ],
        [
          "game",
          "game"
        ],
        [
          "activity",
          "activity"
        ],
        [
          "footbag",
          "footbag"
        ],
        [
          "feet",
          "foot"
        ]
      ],
      "raw_glosses": [
        "(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."
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "games"
      ]
    },
    {
      "categories": [],
      "glosses": [
        "The footbag used for such a game."
      ],
      "id": "en-hacky_sack-en-noun-aDI5uvkN",
      "raw_glosses": [
        "(countable) The footbag used for such a game."
      ],
      "tags": [
        "countable"
      ]
    }
  ],
  "wikipedia": [
    "Wham-O",
    "hacky sack"
  ],
  "word": "hacky sack"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English entries with language name categories using raw markup",
    "English entries with topic categories using raw markup",
    "English genericized trademarks",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "English reduplications",
    "English terms with non-redundant non-automated sortkeys",
    "English uncountable nouns",
    "en:Sports"
  ],
  "etymology_text": "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.",
  "forms": [
    {
      "form": "hacky sacks",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "hacky sack (countable and uncountable, plural hacky sacks)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English uncountable nouns",
        "en:Games"
      ],
      "glosses": [
        "A game or activity in which one or a group of players try to keep a footbag off the ground using only the feet."
      ],
      "links": [
        [
          "games",
          "game#Noun"
        ],
        [
          "game",
          "game"
        ],
        [
          "activity",
          "activity"
        ],
        [
          "footbag",
          "footbag"
        ],
        [
          "feet",
          "foot"
        ]
      ],
      "raw_glosses": [
        "(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."
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "games"
      ]
    },
    {
      "categories": [
        "English countable nouns"
      ],
      "glosses": [
        "The footbag used for such a game."
      ],
      "raw_glosses": [
        "(countable) The footbag used for such a game."
      ],
      "tags": [
        "countable"
      ]
    }
  ],
  "wikipedia": [
    "Wham-O",
    "hacky sack"
  ],
  "word": "hacky sack"
}