"come un fulmine a ciel sereno" meaning in Italien

{
  "categories": [
    {
      "kind": "other",
      "name": "Compositions en italien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Locutions adverbiales en italien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Italien",
      "orig": "italien",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "Composé de come, fulmine, ciel et sereno, littéralement « comme la foudre dans un ciel serein »"
  ],
  "lang": "Italien",
  "lang_code": "it",
  "pos": "adv",
  "pos_title": "Locution adverbiale",
  "senses": [
    {
      "glosses": [
        "Arriver de façon soudaine, par hasard."
      ],
      "id": "fr-come_un_fulmine_a_ciel_sereno-it-adv-n9uYF5~c"
    },
    {
      "categories": [
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en italien",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Arriver au mauvais moment, de manière inopportune."
      ],
      "id": "fr-come_un_fulmine_a_ciel_sereno-it-adv-1ePXF~hr"
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈko.me ˈun ˈful.mi.ne ˈa ˈt͡ʃɛl se.ˈre.no\\"
    }
  ],
  "tags": [
    "invariable"
  ],
  "word": "come un fulmine a ciel sereno"
}

{
  "categories": [
    "Compositions en italien",
    "Locutions adverbiales en italien",
    "italien"
  ],
  "etymology_texts": [
    "Composé de come, fulmine, ciel et sereno, littéralement « comme la foudre dans un ciel serein »"
  ],
  "lang": "Italien",
  "lang_code": "it",
  "pos": "adv",
  "pos_title": "Locution adverbiale",
  "senses": [
    {
      "glosses": [
        "Arriver de façon soudaine, par hasard."
      ]
    },
    {
      "categories": [
        "Wiktionnaire:Exemples manquants en italien"
      ],
      "glosses": [
        "Arriver au mauvais moment, de manière inopportune."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈko.me ˈun ˈful.mi.ne ˈa ˈt͡ʃɛl se.ˈre.no\\"
    }
  ],
  "tags": [
    "invariable"
  ],
  "word": "come un fulmine a ciel sereno"
}