"Jack at a pinch" meaning in English

{
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      "args": {},
      "expansion": "Jack at a pinch",
      "name": "en-prop"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
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      ],
      "examples": [
        {
          "ref": "1839, The Cottager's Monthly Visitor, volume 19, page 270",
          "text": "\"Nay, not I; it is a pretty thing to expect me to wash them; you may take them back again, and say, as Sally had them before, she may wash them now, for me; I am not going to be 'Jack at a pinch,' I can tell you.\"",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A person whose assistance is sought only in an emergency."
      ],
      "id": "en-Jack_at_a_pinch-en-name-csZVxV07",
      "links": [
        [
          "assistance",
          "assistance"
        ],
        [
          "emergency",
          "emergency"
        ]
      ],
      "raw_glosses": [
        "(informal, archaic) A person whose assistance is sought only in an emergency."
      ],
      "related": [
        {
          "word": "in a pinch"
        }
      ],
      "tags": [
        "archaic",
        "informal"
      ]
    }
  ],
  "word": "Jack at a pinch"
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "Jack at a pinch",
      "name": "en-prop"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "related": [
    {
      "word": "in a pinch"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English informal terms",
        "English lemmas",
        "English multiword terms",
        "English proper nouns",
        "English terms with archaic senses",
        "English terms with quotations",
        "English uncountable nouns"
      ],
      "examples": [
        {
          "ref": "1839, The Cottager's Monthly Visitor, volume 19, page 270",
          "text": "\"Nay, not I; it is a pretty thing to expect me to wash them; you may take them back again, and say, as Sally had them before, she may wash them now, for me; I am not going to be 'Jack at a pinch,' I can tell you.\"",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A person whose assistance is sought only in an emergency."
      ],
      "links": [
        [
          "assistance",
          "assistance"
        ],
        [
          "emergency",
          "emergency"
        ]
      ],
      "raw_glosses": [
        "(informal, archaic) A person whose assistance is sought only in an emergency."
      ],
      "tags": [
        "archaic",
        "informal"
      ]
    }
  ],
  "word": "Jack at a pinch"
}