"hyrddyn" meaning in Welsh

{
  "etymology_text": "From hwrdd + -yn.",
  "forms": [
    {
      "form": "hyrddod",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "hyrddiaid",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "hyrddod",
        "pl2": "hyrddiaid"
      },
      "expansion": "hyrddyn m (plural hyrddod or hyrddiaid, not mutable)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Welsh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "cy",
          "name": "Fish",
          "orig": "cy:Fish",
          "parents": [
            "Vertebrates",
            "Chordates",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "mullet, grey mullet"
      ],
      "id": "en-hyrddyn-cy-noun-UxfYNvC4",
      "links": [
        [
          "mullet",
          "mullet"
        ],
        [
          "grey mullet",
          "grey mullet"
        ]
      ],
      "tags": [
        "masculine",
        "not-mutable"
      ]
    }
  ],
  "word": "hyrddyn"
}

{
  "etymology_text": "From hwrdd + -yn.",
  "forms": [
    {
      "form": "hyrddod",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "hyrddiaid",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "hyrddod",
        "pl2": "hyrddiaid"
      },
      "expansion": "hyrddyn m (plural hyrddod or hyrddiaid, not mutable)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Welsh countable nouns",
        "Welsh entries with incorrect language header",
        "Welsh lemmas",
        "Welsh masculine nouns",
        "Welsh non-mutable terms",
        "Welsh nouns",
        "Welsh nouns with red links in their headword lines",
        "cy:Fish"
      ],
      "glosses": [
        "mullet, grey mullet"
      ],
      "links": [
        [
          "mullet",
          "mullet"
        ],
        [
          "grey mullet",
          "grey mullet"
        ]
      ],
      "tags": [
        "masculine",
        "not-mutable"
      ]
    }
  ],
  "word": "hyrddyn"
}