"-ach" meaning in Middle Irish

{
  "descendants": [
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "ga",
            "2": "-ach"
          },
          "expansion": "Irish: -ach",
          "name": "desc"
        }
      ],
      "text": "Irish: -ach"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "gv",
            "2": "-agh"
          },
          "expansion": "Manx: -agh",
          "name": "desc"
        }
      ],
      "text": "Manx: -agh"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "gd",
            "2": "-ach"
          },
          "expansion": "Scottish Gaelic: -ach",
          "name": "desc"
        }
      ],
      "text": "Scottish Gaelic: -ach"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "mga",
        "2": "sga",
        "3": "-ach"
      },
      "expansion": "Old Irish -ach",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "cel-pro",
        "3": "*-ākos"
      },
      "expansion": "Proto-Celtic *-ākos",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "ine-pro",
        "3": "*-eh₂kos"
      },
      "expansion": "Proto-Indo-European *-eh₂kos",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "-óc"
      },
      "expansion": "Doublet of -óc",
      "name": "doublet"
    }
  ],
  "etymology_text": "From Old Irish -ach, from Proto-Celtic *-ākos, from Proto-Indo-European *-eh₂kos, *-eh₂ḱos, from a-stem suffix *-eh₂- + adjectival suffix *-kos, *-ḱos. Doublet of -óc.",
  "head_templates": [
    {
      "args": {
        "1": "mga",
        "2": "suffix"
      },
      "expansion": "-ach",
      "name": "head"
    }
  ],
  "lang": "Middle Irish",
  "lang_code": "mga",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "_dis": "74 26",
          "kind": "other",
          "name": "Middle Irish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "Forms adjectives meaning \"related to, having, characterised by, prone to\"."
      ],
      "id": "en--ach-mga-suffix-mjcm~c49",
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "Forms nouns meaning \"person or thing connected or involved with, belonging to, having\"."
      ],
      "id": "en--ach-mga-suffix-qvTUpgFX",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/əx/"
    }
  ],
  "word": "-ach"
}

{
  "categories": [
    "Middle Irish doublets",
    "Middle Irish entries with incorrect language header",
    "Middle Irish lemmas",
    "Middle Irish suffixes",
    "Middle Irish terms derived from Old Irish",
    "Middle Irish terms derived from Proto-Celtic",
    "Middle Irish terms derived from Proto-Indo-European",
    "Middle Irish terms inherited from Old Irish",
    "Middle Irish terms inherited from Proto-Celtic",
    "Middle Irish terms inherited from Proto-Indo-European",
    "Pages with 7 entries",
    "Pages with entries"
  ],
  "descendants": [
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "ga",
            "2": "-ach"
          },
          "expansion": "Irish: -ach",
          "name": "desc"
        }
      ],
      "text": "Irish: -ach"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "gv",
            "2": "-agh"
          },
          "expansion": "Manx: -agh",
          "name": "desc"
        }
      ],
      "text": "Manx: -agh"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "gd",
            "2": "-ach"
          },
          "expansion": "Scottish Gaelic: -ach",
          "name": "desc"
        }
      ],
      "text": "Scottish Gaelic: -ach"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "mga",
        "2": "sga",
        "3": "-ach"
      },
      "expansion": "Old Irish -ach",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "cel-pro",
        "3": "*-ākos"
      },
      "expansion": "Proto-Celtic *-ākos",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "ine-pro",
        "3": "*-eh₂kos"
      },
      "expansion": "Proto-Indo-European *-eh₂kos",
      "name": "inh"
    },
    {
      "args": {
        "1": "mga",
        "2": "-óc"
      },
      "expansion": "Doublet of -óc",
      "name": "doublet"
    }
  ],
  "etymology_text": "From Old Irish -ach, from Proto-Celtic *-ākos, from Proto-Indo-European *-eh₂kos, *-eh₂ḱos, from a-stem suffix *-eh₂- + adjectival suffix *-kos, *-ḱos. Doublet of -óc.",
  "head_templates": [
    {
      "args": {
        "1": "mga",
        "2": "suffix"
      },
      "expansion": "-ach",
      "name": "head"
    }
  ],
  "lang": "Middle Irish",
  "lang_code": "mga",
  "pos": "suffix",
  "senses": [
    {
      "glosses": [
        "Forms adjectives meaning \"related to, having, characterised by, prone to\"."
      ],
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "Forms nouns meaning \"person or thing connected or involved with, belonging to, having\"."
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/əx/"
    }
  ],
  "word": "-ach"
}