"one's back is up" meaning in English

{
  "etymology_text": "From the way a cat, when angry, raises or arches its back.",
  "head_templates": [
    {
      "args": {
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        "2": "phrase"
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      "expansion": "one's back is up",
      "name": "head"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
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      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
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          "source": "w"
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      "examples": [
        {
          "ref": "1835, William Hayley, The Life and Letters of William Cowper",
          "text": "My back is up, and I cannot hear the thought of wooing him any farther, nor would do it, though he were as pig a gentleman (look you) as Lucifer himself.",
          "type": "quotation"
        },
        {
          "ref": "2011, Jeannie Watt, The Baby Truce, page 84",
          "text": "And I want you to be nice to Patty. For some reason her back is up.",
          "type": "quotation"
        },
        {
          "ref": "2014, Kristin Butcher, Cabin Girl",
          "text": "Now my back is up. “Yes, the witch,” I hiss.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "One is offended or angry."
      ],
      "id": "en-one's_back_is_up-en-phrase-S2fxqlG9",
      "raw_glosses": [
        "(idiomatic) One is offended or angry."
      ],
      "related": [
        {
          "word": "get one's back up"
        }
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "En-au-one's back is up.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/4/43/En-au-one%27s_back_is_up.ogg/En-au-one%27s_back_is_up.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/4/43/En-au-one%27s_back_is_up.ogg",
      "tags": [
        "Australia"
      ],
      "text": "Audio (AU)"
    }
  ],
  "word": "one's back is up"
}

{
  "etymology_text": "From the way a cat, when angry, raises or arches its back.",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "phrase"
      },
      "expansion": "one's back is up",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "related": [
    {
      "word": "get one's back up"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English idioms",
        "English lemmas",
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        "English terms with quotations"
      ],
      "examples": [
        {
          "ref": "1835, William Hayley, The Life and Letters of William Cowper",
          "text": "My back is up, and I cannot hear the thought of wooing him any farther, nor would do it, though he were as pig a gentleman (look you) as Lucifer himself.",
          "type": "quotation"
        },
        {
          "ref": "2011, Jeannie Watt, The Baby Truce, page 84",
          "text": "And I want you to be nice to Patty. For some reason her back is up.",
          "type": "quotation"
        },
        {
          "ref": "2014, Kristin Butcher, Cabin Girl",
          "text": "Now my back is up. “Yes, the witch,” I hiss.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "One is offended or angry."
      ],
      "raw_glosses": [
        "(idiomatic) One is offended or angry."
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "En-au-one's back is up.ogg",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/4/43/En-au-one%27s_back_is_up.ogg/En-au-one%27s_back_is_up.ogg.mp3",
      "ogg_url": "https://upload.wikimedia.org/wikipedia/commons/4/43/En-au-one%27s_back_is_up.ogg",
      "tags": [
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      "text": "Audio (AU)"
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  ],
  "word": "one's back is up"
}