"therein lies the rub" meaning in English

{
  "etymology_text": "Misquotation or paraphrasing from Shakespeare's Hamlet: \"ay, there's the rub\".",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "phrase"
      },
      "expansion": "therein lies the rub",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "I tried to back up my database to a USB flash drive, but it isn't big enough. Therein lies the rub.",
          "type": "example"
        }
      ],
      "glosses": [
        "That is where the problem is."
      ],
      "id": "en-therein_lies_the_rub-en-phrase-2eWVQLzJ",
      "links": [
        [
          "problem",
          "problem"
        ]
      ],
      "related": [
        {
          "word": "thereby hangs a tale"
        },
        {
          "word": "where the shoe pinches"
        }
      ],
      "synonyms": [
        {
          "word": "there lies the rub"
        },
        {
          "word": "there is the rub"
        }
      ],
      "translations": [
        {
          "code": "nl",
          "lang": "Dutch",
          "sense": "that is where the problem is",
          "word": "daar wringt de schoen"
        },
        {
          "code": "nl",
          "lang": "Dutch",
          "sense": "that is where the problem is",
          "word": "daar wringt het schoentje"
        },
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "that is where the problem is",
          "word": "siinä ongelma juuri piileekin"
        },
        {
          "code": "fr",
          "lang": "French",
          "sense": "that is where the problem is",
          "word": "c’est là que le bât blesse"
        },
        {
          "code": "de",
          "lang": "German",
          "sense": "that is where the problem is",
          "word": "da liegt der Hase im Pfeffer"
        },
        {
          "code": "de",
          "lang": "German",
          "sense": "that is where the problem is",
          "word": "da liegt der Hund begraben"
        },
        {
          "code": "el",
          "lang": "Greek",
          "roman": "ta koumpiá tis Aléxainas",
          "sense": "that is where the problem is",
          "word": "τα κουμπιά της Αλέξαινας"
        },
        {
          "code": "hu",
          "english": "van",
          "lang": "Hungarian",
          "sense": "that is where the problem is",
          "word": "itt a bökkenő/gond"
        },
        {
          "code": "hu",
          "lang": "Hungarian",
          "sense": "that is where the problem is",
          "word": "itt van a kutya elásva"
        },
        {
          "code": "it",
          "lang": "Italian",
          "sense": "that is where the problem is",
          "word": "qui casca l'asino"
        },
        {
          "code": "nb",
          "lang": "Norwegian Bokmål",
          "sense": "that is where the problem is",
          "word": "der ligger hunden begravet"
        },
        {
          "code": "pl",
          "lang": "Polish",
          "sense": "that is where the problem is",
          "word": "tu leży pies pogrzebany"
        },
        {
          "code": "pl",
          "lang": "Polish",
          "sense": "that is where the problem is",
          "word": "tu jest pies pogrzebany"
        },
        {
          "code": "ru",
          "lang": "Russian",
          "roman": "vot gde sobáka zarýta",
          "sense": "that is where the problem is",
          "word": "вот где соба́ка зары́та"
        },
        {
          "code": "es",
          "lang": "Spanish",
          "sense": "that is where the problem is",
          "word": "la madre del cordero"
        },
        {
          "code": "sv",
          "lang": "Swedish",
          "sense": "that is where the problem is",
          "word": "här ligger en hund begraven"
        }
      ]
    }
  ],
  "word": "therein lies the rub"
}

{
  "etymology_text": "Misquotation or paraphrasing from Shakespeare's Hamlet: \"ay, there's the rub\".",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "phrase"
      },
      "expansion": "therein lies the rub",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "related": [
    {
      "word": "thereby hangs a tale"
    },
    {
      "word": "where the shoe pinches"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English phrases",
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "I tried to back up my database to a USB flash drive, but it isn't big enough. Therein lies the rub.",
          "type": "example"
        }
      ],
      "glosses": [
        "That is where the problem is."
      ],
      "links": [
        [
          "problem",
          "problem"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "there lies the rub"
    },
    {
      "word": "there is the rub"
    }
  ],
  "translations": [
    {
      "code": "nl",
      "lang": "Dutch",
      "sense": "that is where the problem is",
      "word": "daar wringt de schoen"
    },
    {
      "code": "nl",
      "lang": "Dutch",
      "sense": "that is where the problem is",
      "word": "daar wringt het schoentje"
    },
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "that is where the problem is",
      "word": "siinä ongelma juuri piileekin"
    },
    {
      "code": "fr",
      "lang": "French",
      "sense": "that is where the problem is",
      "word": "c’est là que le bât blesse"
    },
    {
      "code": "de",
      "lang": "German",
      "sense": "that is where the problem is",
      "word": "da liegt der Hase im Pfeffer"
    },
    {
      "code": "de",
      "lang": "German",
      "sense": "that is where the problem is",
      "word": "da liegt der Hund begraben"
    },
    {
      "code": "el",
      "lang": "Greek",
      "roman": "ta koumpiá tis Aléxainas",
      "sense": "that is where the problem is",
      "word": "τα κουμπιά της Αλέξαινας"
    },
    {
      "code": "hu",
      "english": "van",
      "lang": "Hungarian",
      "sense": "that is where the problem is",
      "word": "itt a bökkenő/gond"
    },
    {
      "code": "hu",
      "lang": "Hungarian",
      "sense": "that is where the problem is",
      "word": "itt van a kutya elásva"
    },
    {
      "code": "it",
      "lang": "Italian",
      "sense": "that is where the problem is",
      "word": "qui casca l'asino"
    },
    {
      "code": "nb",
      "lang": "Norwegian Bokmål",
      "sense": "that is where the problem is",
      "word": "der ligger hunden begravet"
    },
    {
      "code": "pl",
      "lang": "Polish",
      "sense": "that is where the problem is",
      "word": "tu leży pies pogrzebany"
    },
    {
      "code": "pl",
      "lang": "Polish",
      "sense": "that is where the problem is",
      "word": "tu jest pies pogrzebany"
    },
    {
      "code": "ru",
      "lang": "Russian",
      "roman": "vot gde sobáka zarýta",
      "sense": "that is where the problem is",
      "word": "вот где соба́ка зары́та"
    },
    {
      "code": "es",
      "lang": "Spanish",
      "sense": "that is where the problem is",
      "word": "la madre del cordero"
    },
    {
      "code": "sv",
      "lang": "Swedish",
      "sense": "that is where the problem is",
      "word": "här ligger en hund begraven"
    }
  ],
  "word": "therein lies the rub"
}