"shift ground" meaning in English

{
  "forms": [
    {
      "form": "shifts ground",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "shifting ground",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "shifted ground",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "shifted ground",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "shift ground (third-person singular simple present shifts ground, present participle shifting ground, simple past and past participle shifted ground)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "alt_of": [
        {
          "word": "shift one's ground"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "Confronted now with a growing list of unhelpful textual clues, Mr. Pereida seeks to shift ground.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of shift one's ground"
      ],
      "id": "en-shift_ground-en-verb-ulPtDZfz",
      "links": [
        [
          "shift one's ground",
          "shift one's ground#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "shift ground"
}

{
  "forms": [
    {
      "form": "shifts ground",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "shifting ground",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "shifted ground",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "shifted ground",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "shift ground (third-person singular simple present shifts ground, present participle shifting ground, simple past and past participle shifted ground)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "alt_of": [
        {
          "word": "shift one's ground"
        }
      ],
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English terms with quotations",
        "English verbs"
      ],
      "examples": [
        {
          "text": "Confronted now with a growing list of unhelpful textual clues, Mr. Pereida seeks to shift ground.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of shift one's ground"
      ],
      "links": [
        [
          "shift one's ground",
          "shift one's ground#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "shift ground"
}