"real McCoy" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "sco",
        "3": "real MacKay",
        "4": "the real MacKay"
      },
      "expansion": "Scots the real MacKay",
      "name": "der"
    }
  ],
  "etymology_text": "Corruption of Scots the real MacKay, this latter attested in 1856 as “A drappie o’ the real MacKay” (A drop of the real MacKay). How “MacKay” became “McCoy” is unclear; first attested in the form “McCoy” in the US in 1908.\nThe term is the subject of many folk etymologies, discussed at the Wikipedia entry.",
  "forms": [
    {
      "form": "the real McCoy",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the real McCoy"
      },
      "expansion": "the real McCoy",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
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          "source": "w"
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          "name": "Undetermined quotations with omitted translation",
          "parents": [
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          "source": "w"
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      ],
      "glosses": [
        "The genuine thing, neither a substitute nor an imitation."
      ],
      "id": "en-real_McCoy-en-noun-VSlYMg99",
      "links": [
        [
          "genuine",
          "genuine"
        ],
        [
          "substitute",
          "substitute"
        ],
        [
          "imitation",
          "imitation"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) The genuine thing, neither a substitute nor an imitation."
      ],
      "synonyms": [
        {
          "word": "real deal"
        },
        {
          "word": "real McKoy"
        },
        {
          "word": "real Macoy"
        }
      ],
      "tags": [
        "idiomatic"
      ],
      "translations": [
        {
          "code": "pl",
          "lang": "Polish",
          "sense": "Translations",
          "tags": [
            "masculine"
          ],
          "word": "autentyk"
        }
      ],
      "wikipedia": [
        "Scottish National Dictionary"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "En-au-real McCoy.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/9/91/En-au-real_McCoy.ogg/En-au-real_McCoy.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/9/91/En-au-real_McCoy.ogg",
      "tags": [
        "Australia"
      ],
      "text": "Audio (AU)"
    }
  ],
  "word": "real McCoy"
}

{
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    {
      "args": {
        "1": "en",
        "2": "sco",
        "3": "real MacKay",
        "4": "the real MacKay"
      },
      "expansion": "Scots the real MacKay",
      "name": "der"
    }
  ],
  "etymology_text": "Corruption of Scots the real MacKay, this latter attested in 1856 as “A drappie o’ the real MacKay” (A drop of the real MacKay). How “MacKay” became “McCoy” is unclear; first attested in the form “McCoy” in the US in 1908.\nThe term is the subject of many folk etymologies, discussed at the Wikipedia entry.",
  "forms": [
    {
      "form": "the real McCoy",
      "tags": [
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      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the real McCoy"
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      "expansion": "the real McCoy",
      "name": "head"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English multiword terms",
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        "English terms derived from Scots",
        "English terms with audio links",
        "Translation table header lacks gloss",
        "Undetermined quotations with omitted translation",
        "Undetermined terms with quotations"
      ],
      "glosses": [
        "The genuine thing, neither a substitute nor an imitation."
      ],
      "links": [
        [
          "genuine",
          "genuine"
        ],
        [
          "substitute",
          "substitute"
        ],
        [
          "imitation",
          "imitation"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) The genuine thing, neither a substitute nor an imitation."
      ],
      "synonyms": [
        {
          "word": "real deal"
        }
      ],
      "tags": [
        "idiomatic"
      ],
      "wikipedia": [
        "Scottish National Dictionary"
      ]
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  ],
  "sounds": [
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      "audio": "En-au-real McCoy.ogg",
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      "tags": [
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      "text": "Audio (AU)"
    }
  ],
  "synonyms": [
    {
      "word": "real McKoy"
    },
    {
      "word": "real Macoy"
    }
  ],
  "translations": [
    {
      "code": "pl",
      "lang": "Polish",
      "sense": "Translations",
      "tags": [
        "masculine"
      ],
      "word": "autentyk"
    }
  ],
  "word": "real McCoy"
}