"jsi" meaning in Czech

{
  "etymology_templates": [
    {
      "args": {
        "1": "cs",
        "2": "sla-pro",
        "3": "*esi"
      },
      "expansion": "Proto-Slavic *esi",
      "name": "inh"
    }
  ],
  "etymology_text": "From Proto-Slavic *esi.",
  "head_templates": [
    {
      "args": {
        "1": "cs",
        "2": "verb form"
      },
      "expansion": "jsi",
      "name": "head"
    }
  ],
  "lang": "Czech",
  "lang_code": "cs",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Czech entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "být"
        }
      ],
      "glosses": [
        "second-person singular present indicative of být"
      ],
      "id": "en-jsi-cs-verb-r3H5nykt",
      "links": [
        [
          "být",
          "být#Czech"
        ]
      ],
      "tags": [
        "form-of",
        "indicative",
        "present",
        "second-person",
        "singular"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[ˈjsɪ]"
    }
  ],
  "word": "jsi"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "cs",
        "2": "sla-pro",
        "3": "*esi"
      },
      "expansion": "Proto-Slavic *esi",
      "name": "inh"
    }
  ],
  "etymology_text": "From Proto-Slavic *esi.",
  "head_templates": [
    {
      "args": {
        "1": "cs",
        "2": "verb form"
      },
      "expansion": "jsi",
      "name": "head"
    }
  ],
  "lang": "Czech",
  "lang_code": "cs",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "Czech entries with incorrect language header",
        "Czech non-lemma forms",
        "Czech terms derived from Proto-Slavic",
        "Czech terms inherited from Proto-Slavic",
        "Czech terms with IPA pronunciation",
        "Czech verb forms",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "form_of": [
        {
          "word": "být"
        }
      ],
      "glosses": [
        "second-person singular present indicative of být"
      ],
      "links": [
        [
          "být",
          "být#Czech"
        ]
      ],
      "tags": [
        "form-of",
        "indicative",
        "present",
        "second-person",
        "singular"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[ˈjsɪ]"
    }
  ],
  "word": "jsi"
}