"declensionism" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "declension",
        "3": "ism"
      },
      "expansion": "declension + -ism",
      "name": "suffix"
    }
  ],
  "etymology_text": "declension + -ism",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "declensionism (uncountable)",
      "name": "en-noun"
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  ],
  "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"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms suffixed with -ism",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2002, Melvyn Stokes, The state of U.S. history, page 74",
          "text": "By breaking free of it, historians could shed the dualisms that now entrap them, and escape the declensionism - the longing for the lost alternative",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A belief in a declining trend in a history."
      ],
      "id": "en-declensionism-en-noun-eJsgI2VZ",
      "related": [
        {
          "word": "declensionist"
        }
      ],
      "tags": [
        "uncountable"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/dɪˈklɛnʃənɪzəm/",
      "tags": [
        "UK"
      ]
    }
  ],
  "word": "declensionism"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "declension",
        "3": "ism"
      },
      "expansion": "declension + -ism",
      "name": "suffix"
    }
  ],
  "etymology_text": "declension + -ism",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "declensionism (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "declensionist"
    }
  ],
  "senses": [
    {
      "categories": [
        "English 5-syllable words",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms suffixed with -ism",
        "English terms with IPA pronunciation",
        "English terms with quotations",
        "English uncountable nouns"
      ],
      "examples": [
        {
          "ref": "2002, Melvyn Stokes, The state of U.S. history, page 74",
          "text": "By breaking free of it, historians could shed the dualisms that now entrap them, and escape the declensionism - the longing for the lost alternative",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A belief in a declining trend in a history."
      ],
      "tags": [
        "uncountable"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/dɪˈklɛnʃənɪzəm/",
      "tags": [
        "UK"
      ]
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  ],
  "word": "declensionism"
}