"на попа" meaning in Russian

{
  "etymology_text": "From на (na) and obsolete поп (pop, “figure in the game of Gorodki”) (named after поп (pop, “priest”)), probably used as euphemism for попа (popa, “butt”).",
  "forms": [
    {
      "form": "на попа ́",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "na popá",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "на попа́"
      },
      "expansion": "на попа́ • (na popá)",
      "name": "ru-adv"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian entries with incorrect language header",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "vertically"
      ],
      "id": "en-на_попа-ru-adv-v0j8UhdL",
      "links": [
        [
          "vertically",
          "vertically"
        ]
      ],
      "synonyms": [
        {
          "word": "вертикально"
        },
        {
          "word": "стоймя"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[nə‿pɐˈpa]"
    }
  ],
  "word": "на попа"
}

{
  "etymology_text": "From на (na) and obsolete поп (pop, “figure in the game of Gorodki”) (named after поп (pop, “priest”)), probably used as euphemism for попа (popa, “butt”).",
  "forms": [
    {
      "form": "на попа ́",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "na popá",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "на попа́"
      },
      "expansion": "на попа́ • (na popá)",
      "name": "ru-adv"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Russian adverbs",
        "Russian entries with incorrect language header",
        "Russian lemmas",
        "Russian multiword terms",
        "Russian terms with IPA pronunciation"
      ],
      "glosses": [
        "vertically"
      ],
      "links": [
        [
          "vertically",
          "vertically"
        ]
      ],
      "synonyms": [
        {
          "word": "вертикально"
        },
        {
          "word": "стоймя"
        }
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[nə‿pɐˈpa]"
    }
  ],
  "word": "на попа"
}