"-կու" meaning in Old Armenian

{
  "etymology_templates": [
    {
      "args": {
        "1": "xcl",
        "2": "",
        "3": "ու"
      },
      "expansion": "+ -ու (-u)",
      "name": "suffix"
    }
  ],
  "etymology_text": "From the augment -կ- (-k-) + -ու (-u).",
  "forms": [
    {
      "form": "-ku",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "xcl",
        "2": "suffix",
        "head": "",
        "sort": "կու",
        "tr": ""
      },
      "expansion": "-կու • (-ku)",
      "name": "head"
    },
    {
      "args": {
        "sort": "կու"
      },
      "expansion": "-կու • (-ku)",
      "name": "xcl-suffix"
    }
  ],
  "lang": "Old Armenian",
  "lang_code": "xcl",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Old Armenian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Old Armenian terms suffixed with -ու",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Old Armenian terms with redundant sortkeys",
          "parents": [
            "Terms with redundant sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "forming adjectives"
      ],
      "id": "en--կու-xcl-suffix-hxD5nE7E",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-կու"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "xcl",
        "2": "",
        "3": "ու"
      },
      "expansion": "+ -ու (-u)",
      "name": "suffix"
    }
  ],
  "etymology_text": "From the augment -կ- (-k-) + -ու (-u).",
  "forms": [
    {
      "form": "-ku",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "xcl",
        "2": "suffix",
        "head": "",
        "sort": "կու",
        "tr": ""
      },
      "expansion": "-կու • (-ku)",
      "name": "head"
    },
    {
      "args": {
        "sort": "կու"
      },
      "expansion": "-կու • (-ku)",
      "name": "xcl-suffix"
    }
  ],
  "lang": "Old Armenian",
  "lang_code": "xcl",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Old Armenian entries with incorrect language header",
        "Old Armenian lemmas",
        "Old Armenian suffixes",
        "Old Armenian terms suffixed with -ու",
        "Old Armenian terms with redundant sortkeys"
      ],
      "glosses": [
        "forming adjectives"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-կու"
}