"字足らず" meaning in 日本語

{
  "categories": [
    {
      "kind": "other",
      "name": "日本語",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "日本語 名詞",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "じたらず"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "noun",
  "pos_title": "名詞",
  "related": [
    {
      "word": "字余り"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "日本語 文学",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "短歌、俳句などで五音の句が四音以下、七音の句が六音以下になること。"
      ],
      "id": "ja-字足らず-ja-noun-r7VM4drE",
      "topics": [
        "literature"
      ]
    }
  ],
  "word": "字足らず"
}

{
  "categories": [
    "日本語",
    "日本語 名詞"
  ],
  "forms": [
    {
      "form": "じたらず"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "noun",
  "pos_title": "名詞",
  "related": [
    {
      "word": "字余り"
    }
  ],
  "senses": [
    {
      "categories": [
        "日本語 文学"
      ],
      "glosses": [
        "短歌、俳句などで五音の句が四音以下、七音の句が六音以下になること。"
      ],
      "topics": [
        "literature"
      ]
    }
  ],
  "word": "字足らず"
}