"-уу" meaning in Yakut

{
  "etymology_templates": [
    {
      "args": {
        "1": "tyv",
        "2": "-ук"
      },
      "expansion": "Tuvan -ук (-uk)",
      "name": "cog"
    },
    {
      "args": {
        "1": "kk",
        "2": "-у"
      },
      "expansion": "Kazakh -у (-u)",
      "name": "cog"
    }
  ],
  "etymology_text": "Cognate with Tuvan -ук (-uk), Kazakh -у (-u), etc.",
  "forms": [
    {
      "form": "-uu",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sah",
        "2": "suffixes"
      },
      "expansion": "-уу • (-uu)",
      "name": "head"
    }
  ],
  "lang": "Yakut",
  "lang_code": "sah",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Yakut entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Used to form gerunds from verbs."
      ],
      "id": "en--уу-sah-suffix-H4shQTw6",
      "links": [
        [
          "gerund",
          "gerund"
        ],
        [
          "verb",
          "verb"
        ]
      ],
      "related": [
        {
          "roman": "-üü",
          "word": "-үү"
        },
        {
          "roman": "-ıı",
          "word": "-ыы"
        },
        {
          "roman": "-ii",
          "word": "-ии"
        }
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-уу"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "tyv",
        "2": "-ук"
      },
      "expansion": "Tuvan -ук (-uk)",
      "name": "cog"
    },
    {
      "args": {
        "1": "kk",
        "2": "-у"
      },
      "expansion": "Kazakh -у (-u)",
      "name": "cog"
    }
  ],
  "etymology_text": "Cognate with Tuvan -ук (-uk), Kazakh -у (-u), etc.",
  "forms": [
    {
      "form": "-uu",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sah",
        "2": "suffixes"
      },
      "expansion": "-уу • (-uu)",
      "name": "head"
    }
  ],
  "lang": "Yakut",
  "lang_code": "sah",
  "pos": "suffix",
  "related": [
    {
      "roman": "-üü",
      "word": "-үү"
    },
    {
      "roman": "-ıı",
      "word": "-ыы"
    },
    {
      "roman": "-ii",
      "word": "-ии"
    }
  ],
  "senses": [
    {
      "categories": [
        "Pages with 2 entries",
        "Pages with entries",
        "Yakut entries with incorrect language header",
        "Yakut lemmas",
        "Yakut suffixes",
        "Yakut vowel harmonic lemmas"
      ],
      "glosses": [
        "Used to form gerunds from verbs."
      ],
      "links": [
        [
          "gerund",
          "gerund"
        ],
        [
          "verb",
          "verb"
        ]
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-уу"
}

{
  "called_from": "form_descriptions/1698",
  "msg": "unrecognized head form: complying with vowel harmony",
  "path": [
    "-уу"
  ],
  "section": "Yakut",
  "subsection": "suffix",
  "title": "-уу",
  "trace": ""
}