"cœur de pierre" meaning in French

{
  "forms": [
    {
      "form": "cœurs de pierre",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "cœur de pierre m (plural cœurs de pierre)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "avoir un cœur de pierre"
        }
      ],
      "examples": [
        {
          "english": "(please add an English translation of this quotation)",
          "ref": "2018, Zaz, Saint-Valentin",
          "text": "J’irai sur l’avenue embrasser les statues. À quoi tient leur salut ? Est-ce à leurs cœurs de pierre, à leurs froides manières ?",
          "type": "quotation"
        }
      ],
      "glosses": [
        "heart of stone (an unemotional person, or their \"heart\" (their cooler emotional nature) itself)"
      ],
      "id": "en-cœur_de_pierre-fr-noun-tRGdTiXS",
      "links": [
        [
          "heart of stone",
          "heart of stone"
        ]
      ],
      "raw_glosses": [
        "(figurative, idiomatic) heart of stone (an unemotional person, or their \"heart\" (their cooler emotional nature) itself)"
      ],
      "tags": [
        "figuratively",
        "idiomatic",
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/kœʁ də pjɛʁ/"
    }
  ],
  "word": "cœur de pierre"
}

{
  "derived": [
    {
      "word": "avoir un cœur de pierre"
    }
  ],
  "forms": [
    {
      "form": "cœurs de pierre",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "cœur de pierre m (plural cœurs de pierre)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French idioms",
        "French lemmas",
        "French masculine nouns",
        "French multiword terms",
        "French nouns",
        "French terms with IPA pronunciation",
        "French terms with quotations",
        "Quotation templates to be cleaned",
        "Requests for translations of French quotations"
      ],
      "examples": [
        {
          "english": "(please add an English translation of this quotation)",
          "ref": "2018, Zaz, Saint-Valentin",
          "text": "J’irai sur l’avenue embrasser les statues. À quoi tient leur salut ? Est-ce à leurs cœurs de pierre, à leurs froides manières ?",
          "type": "quotation"
        }
      ],
      "glosses": [
        "heart of stone (an unemotional person, or their \"heart\" (their cooler emotional nature) itself)"
      ],
      "links": [
        [
          "heart of stone",
          "heart of stone"
        ]
      ],
      "raw_glosses": [
        "(figurative, idiomatic) heart of stone (an unemotional person, or their \"heart\" (their cooler emotional nature) itself)"
      ],
      "tags": [
        "figuratively",
        "idiomatic",
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/kœʁ də pjɛʁ/"
    }
  ],
  "word": "cœur de pierre"
}