"просиньць" meaning in Vieux slave

{
  "categories": [
    {
      "kind": "other",
      "name": "Compositions en vieux slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en vieux slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Vieux slave",
      "orig": "vieux slave",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "lang": "Tchèque",
      "lang_code": "cs",
      "word": "prosinec"
    }
  ],
  "etymology_texts": [
    "Composé de про, pro, синь, sinĭ (« sombre ») et -ьць, -ĭcĭ, littéralement « mois sombre, des jours aux nuits longues »."
  ],
  "lang": "Vieux slave",
  "lang_code": "cu",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "prosinĭcĭ"
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en grec",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Janvier."
      ],
      "id": "fr-просиньць-cu-noun-Rg5l2tM8"
    }
  ],
  "word": "просиньць"
}

{
  "categories": [
    "Compositions en vieux slave",
    "Noms communs en vieux slave",
    "vieux slave"
  ],
  "derived": [
    {
      "lang": "Tchèque",
      "lang_code": "cs",
      "word": "prosinec"
    }
  ],
  "etymology_texts": [
    "Composé de про, pro, синь, sinĭ (« sombre ») et -ьць, -ĭcĭ, littéralement « mois sombre, des jours aux nuits longues »."
  ],
  "lang": "Vieux slave",
  "lang_code": "cu",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "prosinĭcĭ"
  ],
  "senses": [
    {
      "categories": [
        "Wiktionnaire:Exemples manquants en grec"
      ],
      "glosses": [
        "Janvier."
      ]
    }
  ],
  "word": "просиньць"
}