"тяжестями" meaning in Russian

{
  "forms": [
    {
      "form": "тя́жестями",
      "tags": [
        "canonical",
        "feminine",
        "inanimate",
        "plural"
      ]
    },
    {
      "form": "tjážestjami",
      "tags": [
        "romanization"
      ]
    }
  ],
  "heads": [
    {
      "1": "тя́жестями",
      "2": "f-in-p",
      "template_name": "ru-noun form"
    },
    {
      "1": "ru",
      "2": "noun form",
      "g": "f-in-p",
      "g10": "",
      "g11": "",
      "g12": "",
      "g2": "",
      "g3": "",
      "g4": "",
      "g5": "",
      "g6": "",
      "g7": "",
      "g8": "",
      "g9": "",
      "head": "тя́жестями",
      "head2": "",
      "head3": "",
      "head4": "",
      "head5": "",
      "head6": "",
      "template_name": "head",
      "tr": "",
      "tr2": "",
      "tr3": "",
      "tr4": "",
      "tr5": "",
      "tr6": ""
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "noun",
  "senses": [
    {
      "form_of": [
        {
          "extra": "tjážestʹ",
          "word": "тя́жесть"
        }
      ],
      "glosses": [
        "instrumental plural of тя́жесть (tjážestʹ)"
      ],
      "id": "тяжестями-noun",
      "nontopical_categories": [
        "Russian 4-syllable words",
        "Russian non-lemma forms",
        "Russian noun forms",
        "Russian terms with IPA pronunciation"
      ],
      "tags": [
        "form-of",
        "instrumental",
        "plural"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[ˈtʲaʐɨsʲtʲəmʲɪ]"
    }
  ],
  "word": "тяжестями"
}