"big if" meaning in English

{
  "forms": [
    {
      "form": "big ifs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "big if (plural big ifs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1868 Montgomery Schuyler, The Pioneer Church: Or, The Story of a New Parish in the West (Boston: Riverside Press, 1868), p. 2",
          "text": "\"If I were only old enough,\" said Kate, \"and knew enough to teach a day-school, I would begin at once and save half of my money ….\"\n\"Oh!\" Edward replied, \"there's a big if in the way.\""
        },
        {
          "text": "2004, Dale Brown, Dreamland: Strike Zone, HarperCollins, →ISBN, page 217,\n\"If they believe us,\" said the admiral, \"and that's a big if, then we're in a race with them to find this thing. Because if they grab it—\""
        },
        {
          "text": "Coordinate term: small if"
        }
      ],
      "glosses": [
        "An unlikely but necessary condition."
      ],
      "id": "en-big_if-en-noun-1czjlbDb",
      "links": [
        [
          "unlikely",
          "unlikely"
        ],
        [
          "necessary",
          "necessary"
        ],
        [
          "condition",
          "condition"
        ]
      ],
      "related": [
        {
          "word": "tall order"
        }
      ],
      "translations": [
        {
          "code": "da",
          "lang": "Danish",
          "sense": "unlikely but necessary condition",
          "tags": [
            "neuter"
          ],
          "word": "stort spørgsmålstegn"
        },
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "unlikely but necessary condition",
          "tags": [
            "uncommon"
          ],
          "word": "iso jos"
        },
        {
          "code": "pl",
          "lang": "Polish",
          "sense": "unlikely but necessary condition",
          "tags": [
            "feminine"
          ],
          "word": "wielka niewiadoma"
        }
      ]
    }
  ],
  "word": "big if"
}

{
  "forms": [
    {
      "form": "big ifs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "big if (plural big ifs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "tall order"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns"
      ],
      "examples": [
        {
          "ref": "1868 Montgomery Schuyler, The Pioneer Church: Or, The Story of a New Parish in the West (Boston: Riverside Press, 1868), p. 2",
          "text": "\"If I were only old enough,\" said Kate, \"and knew enough to teach a day-school, I would begin at once and save half of my money ….\"\n\"Oh!\" Edward replied, \"there's a big if in the way.\""
        },
        {
          "text": "2004, Dale Brown, Dreamland: Strike Zone, HarperCollins, →ISBN, page 217,\n\"If they believe us,\" said the admiral, \"and that's a big if, then we're in a race with them to find this thing. Because if they grab it—\""
        },
        {
          "text": "Coordinate term: small if"
        }
      ],
      "glosses": [
        "An unlikely but necessary condition."
      ],
      "links": [
        [
          "unlikely",
          "unlikely"
        ],
        [
          "necessary",
          "necessary"
        ],
        [
          "condition",
          "condition"
        ]
      ]
    }
  ],
  "translations": [
    {
      "code": "da",
      "lang": "Danish",
      "sense": "unlikely but necessary condition",
      "tags": [
        "neuter"
      ],
      "word": "stort spørgsmålstegn"
    },
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "unlikely but necessary condition",
      "tags": [
        "uncommon"
      ],
      "word": "iso jos"
    },
    {
      "code": "pl",
      "lang": "Polish",
      "sense": "unlikely but necessary condition",
      "tags": [
        "feminine"
      ],
      "word": "wielka niewiadoma"
    }
  ],
  "word": "big if"
}