"whoa back" meaning in English

{
  "lang": "English",
  "lang_code": "en",
  "pos": "intj",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "name": "English animal commands",
          "parents": [
            "Animal commands",
            "Interjections",
            "Communication",
            "Lemmas",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Called when riding an animal to warn anybody following behind that one is about to come to a stop."
      ],
      "id": "en-whoa_back-en-intj-LmIrJbUY",
      "links": [
        [
          "riding",
          "ride"
        ],
        [
          "warn",
          "warn"
        ],
        [
          "stop",
          "stop"
        ]
      ],
      "synonyms": [
        {
          "word": "ho back"
        }
      ]
    }
  ],
  "word": "whoa back"
}

{
  "lang": "English",
  "lang_code": "en",
  "pos": "intj",
  "senses": [
    {
      "categories": [
        "English animal commands",
        "English entries with incorrect language header",
        "English interjections",
        "English lemmas",
        "English multiword terms"
      ],
      "glosses": [
        "Called when riding an animal to warn anybody following behind that one is about to come to a stop."
      ],
      "links": [
        [
          "riding",
          "ride"
        ],
        [
          "warn",
          "warn"
        ],
        [
          "stop",
          "stop"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "ho back"
    }
  ],
  "word": "whoa back"
}