"not've" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "not",
        "3": "'ve"
      },
      "expansion": "not + -'ve",
      "name": "suffix"
    }
  ],
  "etymology_text": "not + -'ve",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "contraction",
        "head": ""
      },
      "expansion": "not've",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "not've",
      "name": "en-cont"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "contraction",
  "senses": [
    {
      "alt_of": [
        {
          "word": "not have"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms suffixed with -'ve",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1998, David Weber, The War God's Own, →ISBN:",
          "text": "I'd not've fallen in if you'd've told me it was there, Da. And I'd not've sunk if you'd've taught me how to swim.",
          "type": "quote"
        },
        {
          "ref": "2005, George Singleton, Novel:",
          "text": "Mac McAdams might not've added all those \"ayes,\" but he spoke in such a melodious dialect that \"aye\" kind of came out understood.",
          "type": "quote"
        },
        {
          "ref": "2018, MST3K, Turkey Day, and 30 years of taking over the world before pie is served:",
          "text": "“To the fan, did it add that much value?” Nelson wondered. “Was it worth that much time? I don’t know. It might not’ve.”",
          "type": "quote"
        }
      ],
      "glosses": [
        "Contraction of not have."
      ],
      "id": "en-not've-en-contraction-7O2hVR9w",
      "links": [
        [
          "not",
          "not#English"
        ],
        [
          "have",
          "have#English"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "contraction"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈnɑtəv/",
      "tags": [
        "US"
      ]
    },
    {
      "ipa": "/ˈnɒtəv/",
      "tags": [
        "Received-Pronunciation"
      ]
    }
  ],
  "word": "not've"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "not",
        "3": "'ve"
      },
      "expansion": "not + -'ve",
      "name": "suffix"
    }
  ],
  "etymology_text": "not + -'ve",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "contraction",
        "head": ""
      },
      "expansion": "not've",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "not've",
      "name": "en-cont"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "contraction",
  "senses": [
    {
      "alt_of": [
        {
          "word": "not have"
        }
      ],
      "categories": [
        "English contractions",
        "English entries with incorrect language header",
        "English non-lemma forms",
        "English terms suffixed with -'ve",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "1998, David Weber, The War God's Own, →ISBN:",
          "text": "I'd not've fallen in if you'd've told me it was there, Da. And I'd not've sunk if you'd've taught me how to swim.",
          "type": "quote"
        },
        {
          "ref": "2005, George Singleton, Novel:",
          "text": "Mac McAdams might not've added all those \"ayes,\" but he spoke in such a melodious dialect that \"aye\" kind of came out understood.",
          "type": "quote"
        },
        {
          "ref": "2018, MST3K, Turkey Day, and 30 years of taking over the world before pie is served:",
          "text": "“To the fan, did it add that much value?” Nelson wondered. “Was it worth that much time? I don’t know. It might not’ve.”",
          "type": "quote"
        }
      ],
      "glosses": [
        "Contraction of not have."
      ],
      "links": [
        [
          "not",
          "not#English"
        ],
        [
          "have",
          "have#English"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "contraction"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈnɑtəv/",
      "tags": [
        "US"
      ]
    },
    {
      "ipa": "/ˈnɒtəv/",
      "tags": [
        "Received-Pronunciation"
      ]
    }
  ],
  "word": "not've"
}