"неистово" meaning in Russian

{
  "etymology_templates": [
    {
      "args": {
        "1": "ru",
        "2": "неи́стовый",
        "3": "-о"
      },
      "expansion": "неи́стовый (neístovyj) + -о (-o)",
      "name": "af"
    }
  ],
  "etymology_text": "неи́стовый (neístovyj) + -о (-o)",
  "forms": [
    {
      "form": "неи́стово",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "neístovo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "неи́стово"
      },
      "expansion": "неи́стово • (neístovo)",
      "name": "ru-adv"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian terms suffixed with -о",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "furiously, violently"
      ],
      "id": "en-неистово-ru-adv-w-3Qspfj",
      "links": [
        [
          "furiously",
          "furiously"
        ],
        [
          "violently",
          "violently"
        ]
      ],
      "related": [
        {
          "roman": "neístovyj",
          "word": "неи́стовый"
        },
        {
          "roman": "ístovyj",
          "word": "и́стовый"
        },
        {
          "roman": "ístina",
          "tags": [
            "feminine"
          ],
          "word": "и́стина"
        },
        {
          "roman": "ístinnyj",
          "word": "и́стинный"
        },
        {
          "roman": "ístinno",
          "word": "и́стинно"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[nʲɪˈistəvə]"
    },
    {
      "audio": "Ru-неистово.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/7/7d/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/7/7d/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg"
    }
  ],
  "word": "неистово"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "ru",
        "2": "неи́стовый",
        "3": "-о"
      },
      "expansion": "неи́стовый (neístovyj) + -о (-o)",
      "name": "af"
    }
  ],
  "etymology_text": "неи́стовый (neístovyj) + -о (-o)",
  "forms": [
    {
      "form": "неи́стово",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "neístovo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "неи́стово"
      },
      "expansion": "неи́стово • (neístovo)",
      "name": "ru-adv"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adv",
  "related": [
    {
      "roman": "neístovyj",
      "word": "неи́стовый"
    },
    {
      "roman": "ístovyj",
      "word": "и́стовый"
    },
    {
      "roman": "ístina",
      "tags": [
        "feminine"
      ],
      "word": "и́стина"
    },
    {
      "roman": "ístinnyj",
      "word": "и́стинный"
    },
    {
      "roman": "ístinno",
      "word": "и́стинно"
    }
  ],
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Russian 4-syllable words",
        "Russian adverbs",
        "Russian entries with incorrect language header",
        "Russian lemmas",
        "Russian terms suffixed with -о",
        "Russian terms with IPA pronunciation"
      ],
      "glosses": [
        "furiously, violently"
      ],
      "links": [
        [
          "furiously",
          "furiously"
        ],
        [
          "violently",
          "violently"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[nʲɪˈistəvə]"
    },
    {
      "audio": "Ru-неистово.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/7/7d/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/7/7d/Ru-%D0%BD%D0%B5%D0%B8%D1%81%D1%82%D0%BE%D0%B2%D0%BE.ogg"
    }
  ],
  "word": "неистово"
}