"zesko" meaning in Breton

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de verbes en breton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Breton",
      "orig": "breton",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "desko",
      "tags": [
        "unmutated"
      ]
    },
    {
      "form": "tesko",
      "tags": [
        "mutation-hard"
      ]
    }
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "verb",
  "pos_title": "Forme de verbe",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Exemples en breton",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "Jules Gros, Le trésor du breton parlé - Deuxième partie - Dictionnaire breton-français des expressions figurées, 1ère ed. 1970, p. 97",
          "text": "Nebaon, me a zesko deoh mond da flata ahanon !",
          "translation": "N’ayez crainte, je vous apprendrai à me dénoncer !"
        }
      ],
      "form_of": [
        {
          "word": "desko"
        }
      ],
      "glosses": [
        "Forme mutée de desko par adoucissement (d > z)."
      ],
      "id": "fr-zesko-br-verb-lcLDAhhl"
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈzes.ko\\"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "zesko"
}

{
  "categories": [
    "Formes de verbes en breton",
    "breton"
  ],
  "forms": [
    {
      "form": "desko",
      "tags": [
        "unmutated"
      ]
    },
    {
      "form": "tesko",
      "tags": [
        "mutation-hard"
      ]
    }
  ],
  "lang": "Breton",
  "lang_code": "br",
  "pos": "verb",
  "pos_title": "Forme de verbe",
  "senses": [
    {
      "categories": [
        "Exemples en breton"
      ],
      "examples": [
        {
          "ref": "Jules Gros, Le trésor du breton parlé - Deuxième partie - Dictionnaire breton-français des expressions figurées, 1ère ed. 1970, p. 97",
          "text": "Nebaon, me a zesko deoh mond da flata ahanon !",
          "translation": "N’ayez crainte, je vous apprendrai à me dénoncer !"
        }
      ],
      "form_of": [
        {
          "word": "desko"
        }
      ],
      "glosses": [
        "Forme mutée de desko par adoucissement (d > z)."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\ˈzes.ko\\"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "zesko"
}