"sinceras" meaning in Portugais

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes d’adjectifs en portugais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Portugais",
      "orig": "portugais",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "Masculin",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "sincero",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "sinceros"
    },
    {
      "form": "Féminin",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "sincera",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Portugais",
  "lang_code": "pt",
  "pos": "adj",
  "pos_title": "Forme d’adjectif",
  "senses": [
    {
      "form_of": [
        {
          "word": "sincero"
        }
      ],
      "glosses": [
        "Féminin pluriel de sincero."
      ],
      "id": "fr-sinceras-pt-adj-we3p9ztX"
    }
  ],
  "sounds": [
    {
      "ipa": "\\sĩ.sˈɛ.ɾɐʃ\\"
    },
    {
      "ipa": "\\sĩ.sˈɛ.ɾəs\\"
    }
  ],
  "tags": [
    "feminine",
    "form-of"
  ],
  "word": "sinceras"
}

{
  "categories": [
    "Formes d’adjectifs en portugais",
    "portugais"
  ],
  "forms": [
    {
      "form": "Masculin",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "sincero",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "sinceros"
    },
    {
      "form": "Féminin",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "sincera",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Portugais",
  "lang_code": "pt",
  "pos": "adj",
  "pos_title": "Forme d’adjectif",
  "senses": [
    {
      "form_of": [
        {
          "word": "sincero"
        }
      ],
      "glosses": [
        "Féminin pluriel de sincero."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\sĩ.sˈɛ.ɾɐʃ\\"
    },
    {
      "ipa": "\\sĩ.sˈɛ.ɾəs\\"
    }
  ],
  "tags": [
    "feminine",
    "form-of"
  ],
  "word": "sinceras"
}