"main morte" meaning in Français

{
  "anagrams": [
    {
      "word": "marmotine"
    },
    {
      "word": "miameront"
    },
    {
      "word": "nommerait"
    },
    {
      "word": "renommait"
    }
  ],
  "categories": [
    {
      "kind": "other",
      "name": "Idiotismes corporels en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Locutions nominales en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Français",
      "orig": "français",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "word": "ne pas y aller de main morte"
    }
  ],
  "etymology_texts": [
    "De main et mort."
  ],
  "forms": [
    {
      "form": "mains mortes",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Français",
  "lang_code": "fr",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "examples": [
        {
          "text": "On disait aux petits enfants : Faites main morte."
        }
      ],
      "glosses": [
        "Main qu’on laisse aller au gré d’une personne qui l’agite, comme si elle était sans nerfs et sans vie."
      ],
      "id": "fr-main_morte-fr-noun-8HgQnfWA"
    }
  ],
  "sounds": [
    {
      "ipa": "\\mɛ̃ mɔʁt\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "main morte"
}

{
  "anagrams": [
    {
      "word": "marmotine"
    },
    {
      "word": "miameront"
    },
    {
      "word": "nommerait"
    },
    {
      "word": "renommait"
    }
  ],
  "categories": [
    "Idiotismes corporels en français",
    "Locutions nominales en français",
    "français"
  ],
  "derived": [
    {
      "word": "ne pas y aller de main morte"
    }
  ],
  "etymology_texts": [
    "De main et mort."
  ],
  "forms": [
    {
      "form": "mains mortes",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Français",
  "lang_code": "fr",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "examples": [
        {
          "text": "On disait aux petits enfants : Faites main morte."
        }
      ],
      "glosses": [
        "Main qu’on laisse aller au gré d’une personne qui l’agite, comme si elle était sans nerfs et sans vie."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\mɛ̃ mɔʁt\\"
    }
  ],
  "tags": [
    "feminine"
  ],
  "word": "main morte"
}