"je ne sais quoi" meaning in French

{
  "etymology_templates": [
    {
      "args": {
        "1": "I don't know what"
      },
      "expansion": "“I don't know what”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "I don't know what"
      },
      "expansion": "Literally, “I don't know what”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “I don't know what”.",
  "forms": [
    {
      "form": "je ne sais quoi",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "#"
      },
      "expansion": "je ne sais quoi m (plural je ne sais quoi)",
      "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"
        }
      ],
      "examples": [
        {
          "english": "If you have it, you have it, Ella she has it. This I don't know what. That the others don't have.",
          "ref": "1987, Michel Berger (lyrics and music), “Ella, elle l'a”, in Babacar, performed by France Gall",
          "text": "Si tu l’as, tu l’as, Ella elle l’a / Ce je ne sais quoi / Que d’autres n’ont pas",
          "type": "quotation"
        }
      ],
      "glosses": [
        "a certain something, je ne sais quoi (intangible quality that makes something distinctive)"
      ],
      "id": "en-je_ne_sais_quoi-fr-noun-lDcovqh7",
      "links": [
        [
          "je ne sais quoi",
          "je ne sais quoi#English"
        ]
      ],
      "related": [
        {
          "word": "je ne sais pas"
        }
      ],
      "synonyms": [
        {
          "word": "Dieu sait quoi"
        },
        {
          "word": "on ne sait quoi"
        },
        {
          "word": "je-ne-sais-quoi"
        }
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ʒə n(ə) sɛ kwa/"
    },
    {
      "rhymes": "-a"
    },
    {
      "audio": "LL-Q150 (fra)-WikiLucas00-je ne sais quoi.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/0/0f/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/0/0f/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav.ogg",
      "text": "Audio"
    }
  ],
  "word": "je ne sais quoi"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "I don't know what"
      },
      "expansion": "“I don't know what”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "I don't know what"
      },
      "expansion": "Literally, “I don't know what”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “I don't know what”.",
  "forms": [
    {
      "form": "je ne sais quoi",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "#"
      },
      "expansion": "je ne sais quoi m (plural je ne sais quoi)",
      "name": "fr-noun"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "noun",
  "related": [
    {
      "word": "je ne sais pas"
    }
  ],
  "senses": [
    {
      "categories": [
        "French countable nouns",
        "French entries with incorrect language header",
        "French lemmas",
        "French masculine nouns",
        "French multiword terms",
        "French nouns",
        "French terms with IPA pronunciation",
        "French terms with audio links",
        "French terms with quotations",
        "Rhymes:French/a",
        "Rhymes:French/a/4 syllables"
      ],
      "examples": [
        {
          "english": "If you have it, you have it, Ella she has it. This I don't know what. That the others don't have.",
          "ref": "1987, Michel Berger (lyrics and music), “Ella, elle l'a”, in Babacar, performed by France Gall",
          "text": "Si tu l’as, tu l’as, Ella elle l’a / Ce je ne sais quoi / Que d’autres n’ont pas",
          "type": "quotation"
        }
      ],
      "glosses": [
        "a certain something, je ne sais quoi (intangible quality that makes something distinctive)"
      ],
      "links": [
        [
          "je ne sais quoi",
          "je ne sais quoi#English"
        ]
      ],
      "synonyms": [
        {
          "word": "Dieu sait quoi"
        },
        {
          "word": "on ne sait quoi"
        }
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ʒə n(ə) sɛ kwa/"
    },
    {
      "rhymes": "-a"
    },
    {
      "audio": "LL-Q150 (fra)-WikiLucas00-je ne sais quoi.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/0/0f/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/0/0f/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav/LL-Q150_%28fra%29-WikiLucas00-je_ne_sais_quoi.wav.ogg",
      "text": "Audio"
    }
  ],
  "synonyms": [
    {
      "word": "je-ne-sais-quoi"
    }
  ],
  "word": "je ne sais quoi"
}