"passer comme une lettre à la poste" meaning in French

{
  "etymology_templates": [
    {
      "args": {
        "1": "to go like a letter in the mail"
      },
      "expansion": "“to go like a letter in the mail”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "to go like a letter in the mail"
      },
      "expansion": "Literally, “to go like a letter in the mail”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “to go like a letter in the mail”.",
  "head_templates": [
    {
      "args": {},
      "expansion": "passer comme une lettre à la poste",
      "name": "fr-verb"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "French entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "French similes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "to go very well, without a hitch; to hit the spot, to be just the thing"
      ],
      "id": "en-passer_comme_une_lettre_à_la_poste-fr-verb-GgzV~Yxt",
      "links": [
        [
          "well",
          "well"
        ],
        [
          "without a hitch",
          "without a hitch"
        ],
        [
          "hit the spot",
          "hit the spot"
        ],
        [
          "just the thing",
          "the thing"
        ]
      ],
      "qualifier": "simile",
      "raw_glosses": [
        "(informal, simile) to go very well, without a hitch; to hit the spot, to be just the thing"
      ],
      "synonyms": [
        {
          "word": "aller tout seul"
        },
        {
          "word": "passer crème"
        }
      ],
      "tags": [
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/pa.se kɔ.m‿yn lɛ.tʁ‿a la pɔst/"
    },
    {
      "ipa": "/pɑ.se kɔ.m‿yn lɛ.tʁ‿a la pɔst/"
    },
    {
      "audio": "LL-Q150 (fra)-Lyokoï-passer comme une lettre à la poste.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/a/a6/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/a/a6/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav.ogg"
    }
  ],
  "word": "passer comme une lettre à la poste"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "to go like a letter in the mail"
      },
      "expansion": "“to go like a letter in the mail”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "to go like a letter in the mail"
      },
      "expansion": "Literally, “to go like a letter in the mail”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “to go like a letter in the mail”.",
  "head_templates": [
    {
      "args": {},
      "expansion": "passer comme une lettre à la poste",
      "name": "fr-verb"
    }
  ],
  "lang": "French",
  "lang_code": "fr",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "French entries with incorrect language header",
        "French informal terms",
        "French lemmas",
        "French multiword terms",
        "French similes",
        "French terms with IPA pronunciation",
        "French verbs",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "to go very well, without a hitch; to hit the spot, to be just the thing"
      ],
      "links": [
        [
          "well",
          "well"
        ],
        [
          "without a hitch",
          "without a hitch"
        ],
        [
          "hit the spot",
          "hit the spot"
        ],
        [
          "just the thing",
          "the thing"
        ]
      ],
      "qualifier": "simile",
      "raw_glosses": [
        "(informal, simile) to go very well, without a hitch; to hit the spot, to be just the thing"
      ],
      "synonyms": [
        {
          "word": "aller tout seul"
        },
        {
          "word": "passer crème"
        }
      ],
      "tags": [
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/pa.se kɔ.m‿yn lɛ.tʁ‿a la pɔst/"
    },
    {
      "ipa": "/pɑ.se kɔ.m‿yn lɛ.tʁ‿a la pɔst/"
    },
    {
      "audio": "LL-Q150 (fra)-Lyokoï-passer comme une lettre à la poste.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/a/a6/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/a/a6/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav/LL-Q150_%28fra%29-Lyoko%C3%AF-passer_comme_une_lettre_%C3%A0_la_poste.wav.ogg"
    }
  ],
  "word": "passer comme une lettre à la poste"
}