"a ojo" meaning in Spanish

{
  "etymology_templates": [
    {
      "args": {
        "1": "to 􂀿the􂁀 eye"
      },
      "expansion": "“to [the] eye”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "to 􂀿the􂁀 eye"
      },
      "expansion": "Literally, “to [the] eye”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “to [the] eye”.",
  "head_templates": [
    {
      "args": {},
      "expansion": "a ojo",
      "name": "es-adv"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Spanish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "roughly; at a rough guess"
      ],
      "id": "en-a_ojo-es-adv-dRveLL5J",
      "links": [
        [
          "roughly",
          "roughly"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) roughly; at a rough guess"
      ],
      "synonyms": [
        {
          "word": "a bulto"
        },
        {
          "word": "a ojímetro"
        },
        {
          "word": "a ojo de buen cubero"
        }
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "word": "a ojo"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "to 􂀿the􂁀 eye"
      },
      "expansion": "“to [the] eye”",
      "name": "m-g"
    },
    {
      "args": {
        "1": "to 􂀿the􂁀 eye"
      },
      "expansion": "Literally, “to [the] eye”",
      "name": "lit"
    }
  ],
  "etymology_text": "Literally, “to [the] eye”.",
  "head_templates": [
    {
      "args": {},
      "expansion": "a ojo",
      "name": "es-adv"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        "Spanish adverbs",
        "Spanish entries with incorrect language header",
        "Spanish idioms",
        "Spanish lemmas",
        "Spanish multiword terms"
      ],
      "glosses": [
        "roughly; at a rough guess"
      ],
      "links": [
        [
          "roughly",
          "roughly"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) roughly; at a rough guess"
      ],
      "synonyms": [
        {
          "word": "a bulto"
        },
        {
          "word": "a ojímetro"
        },
        {
          "word": "a ojo de buen cubero"
        }
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "word": "a ojo"
}