"can't carry a tune in a bucket" meaning in English

{
  "forms": [
    {
      "form": "can't carry a tune in a bucket",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "couldn't carry a tune in a bucket",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "can't<can't,-,couldn't,-> carry a tune in a bucket"
      },
      "expansion": "can't carry a tune in a bucket (third-person singular simple present can't carry a tune in a bucket, no present participle, simple past couldn't carry a tune in a bucket, no past participle)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English negative polarity items",
          "parents": [
            "Negative polarity items",
            "Terms by semantic function"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Finnish translations",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with French translations",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Sings very badly."
      ],
      "id": "en-can't_carry_a_tune_in_a_bucket-en-verb-rR~Vdwh8",
      "links": [
        [
          "Sings",
          "sing"
        ],
        [
          "badly",
          "badly"
        ]
      ],
      "raw_glosses": [
        "(idiomatic, slang) Sings very badly."
      ],
      "related": [
        {
          "word": "carry a tune"
        },
        {
          "word": "couldn't carry a note in a bucket"
        },
        {
          "word": "tin ear"
        }
      ],
      "tags": [
        "idiomatic",
        "no-past-participle",
        "no-present-participle",
        "slang"
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "Translations",
          "word": "laulaa kuin varis"
        },
        {
          "code": "fr",
          "lang": "French",
          "sense": "Translations",
          "word": "chanter comme une casserole"
        }
      ]
    }
  ],
  "word": "can't carry a tune in a bucket"
}

{
  "forms": [
    {
      "form": "can't carry a tune in a bucket",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "couldn't carry a tune in a bucket",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "can't<can't,-,couldn't,-> carry a tune in a bucket"
      },
      "expansion": "can't carry a tune in a bucket (third-person singular simple present can't carry a tune in a bucket, no present participle, simple past couldn't carry a tune in a bucket, no past participle)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "related": [
    {
      "word": "carry a tune"
    },
    {
      "word": "couldn't carry a note in a bucket"
    },
    {
      "word": "tin ear"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English idioms",
        "English lemmas",
        "English multiword terms",
        "English negative polarity items",
        "English slang",
        "English verbs",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Finnish translations",
        "Terms with French translations",
        "Translation table header lacks gloss"
      ],
      "glosses": [
        "Sings very badly."
      ],
      "links": [
        [
          "Sings",
          "sing"
        ],
        [
          "badly",
          "badly"
        ]
      ],
      "raw_glosses": [
        "(idiomatic, slang) Sings very badly."
      ],
      "tags": [
        "idiomatic",
        "no-past-participle",
        "no-present-participle",
        "slang"
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "Translations",
      "word": "laulaa kuin varis"
    },
    {
      "code": "fr",
      "lang": "French",
      "sense": "Translations",
      "word": "chanter comme une casserole"
    }
  ],
  "word": "can't carry a tune in a bucket"
}