"dark sleeper" meaning in English

{
  "forms": [
    {
      "form": "dark sleepers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "dark sleeper (plural dark sleepers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
        },
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          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
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        },
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          "parents": [],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Gobies",
          "orig": "en:Gobies",
          "parents": [
            "Fish",
            "Vertebrates",
            "Chordates",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1980, Jiro Kikkawa, Comparative Ecology, translation of original by Yoshiaki Ito, →ISBN, page 218:",
          "text": "In these species the eggs are defended most strongly, and feeding territories have also been reported for some of them (the dark sleeper and the common freshwater goby).",
          "type": "quote"
        }
      ],
      "glosses": [
        "Odontobutis obscura, a freshwater goby found in East Asia"
      ],
      "hypernyms": [
        {
          "sense": "perciform",
          "word": "actinopterygian"
        },
        {
          "word": "sleeper"
        },
        {
          "word": "goby"
        },
        {
          "word": "fish"
        }
      ],
      "id": "en-dark_sleeper-en-noun-jP1bZuJ-",
      "links": [
        [
          "goby",
          "goby"
        ],
        [
          "East Asia",
          "East Asia"
        ]
      ],
      "translations": [
        {
          "code": "ko",
          "lang": "Korean",
          "roman": "nambangdongsari",
          "sense": "Odontobutis obscura",
          "word": "남방동사리"
        }
      ],
      "wikipedia": [
        "Odontobutis obscura"
      ]
    }
  ],
  "word": "dark sleeper"
}

{
  "forms": [
    {
      "form": "dark sleepers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "dark sleeper (plural dark sleepers)",
      "name": "en-noun"
    }
  ],
  "hypernyms": [
    {
      "sense": "perciform",
      "word": "actinopterygian"
    },
    {
      "word": "sleeper"
    },
    {
      "word": "goby"
    },
    {
      "word": "fish"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English countable nouns",
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        "English nouns",
        "English terms with quotations",
        "Entries using missing taxonomic name (species)",
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        "Pages with 1 entry",
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        "Terms with Korean translations",
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      ],
      "examples": [
        {
          "ref": "1980, Jiro Kikkawa, Comparative Ecology, translation of original by Yoshiaki Ito, →ISBN, page 218:",
          "text": "In these species the eggs are defended most strongly, and feeding territories have also been reported for some of them (the dark sleeper and the common freshwater goby).",
          "type": "quote"
        }
      ],
      "glosses": [
        "Odontobutis obscura, a freshwater goby found in East Asia"
      ],
      "links": [
        [
          "goby",
          "goby"
        ],
        [
          "East Asia",
          "East Asia"
        ]
      ],
      "wikipedia": [
        "Odontobutis obscura"
      ]
    }
  ],
  "translations": [
    {
      "code": "ko",
      "lang": "Korean",
      "roman": "nambangdongsari",
      "sense": "Odontobutis obscura",
      "word": "남방동사리"
    }
  ],
  "word": "dark sleeper"
}