"exercise in futility" meaning in English

{
  "forms": [
    {
      "form": "exercises in futility",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "exercises in futility"
      },
      "expansion": "exercise in futility (plural exercises in futility)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2009 August 8, Tahereh Ghanaati, “The War in Afghanistan: An Exercise in Futility”, in Press TV:",
          "text": "Many feel that the continued war in Afghanistan is nothing more than an exercise in futility - and with good reason.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A course of action doomed to be futile."
      ],
      "id": "en-exercise_in_futility-en-noun-CaDmb8Do",
      "links": [
        [
          "action",
          "action"
        ],
        [
          "doom",
          "doom"
        ],
        [
          "futile",
          "futile"
        ]
      ],
      "related": [
        {
          "word": "wild-goose chase"
        }
      ]
    }
  ],
  "word": "exercise in futility"
}

{
  "forms": [
    {
      "form": "exercises in futility",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "exercises in futility"
      },
      "expansion": "exercise in futility (plural exercises in futility)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "wild-goose chase"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "2009 August 8, Tahereh Ghanaati, “The War in Afghanistan: An Exercise in Futility”, in Press TV:",
          "text": "Many feel that the continued war in Afghanistan is nothing more than an exercise in futility - and with good reason.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A course of action doomed to be futile."
      ],
      "links": [
        [
          "action",
          "action"
        ],
        [
          "doom",
          "doom"
        ],
        [
          "futile",
          "futile"
        ]
      ]
    }
  ],
  "word": "exercise in futility"
}