"-zi" meaning in Swahili

{
  "etymology_text": "What are now vowel-final verb stems originally had an -l-, which resurfaces whenever a suffix is added. After addition of the suffix -i, this -l- was then spirantized to -z-.",
  "head_templates": [
    {
      "args": {
        "1": "sw",
        "2": "suffix"
      },
      "expansion": "-zi",
      "name": "head"
    }
  ],
  "lang": "Swahili",
  "lang_code": "sw",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Swahili entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "-kimbia (“to run”) + -zi → mkimbizi (“refugee”)",
          "type": "example"
        },
        {
          "text": "-teua (“to choose”) + -zi → uteuzi (“nomination”)",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix used after a vowel in nominal forms of verbs, in conjunction with a noun class prefix"
      ],
      "id": "en--zi-sw-suffix-s8eIN7bV",
      "synonyms": [
        {
          "sense": "after a consonant",
          "word": "-i"
        }
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-zi"
}

{
  "etymology_text": "What are now vowel-final verb stems originally had an -l-, which resurfaces whenever a suffix is added. After addition of the suffix -i, this -l- was then spirantized to -z-.",
  "head_templates": [
    {
      "args": {
        "1": "sw",
        "2": "suffix"
      },
      "expansion": "-zi",
      "name": "head"
    }
  ],
  "lang": "Swahili",
  "lang_code": "sw",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "Pages with 2 entries",
        "Pages with entries",
        "Swahili entries with incorrect language header",
        "Swahili lemmas",
        "Swahili suffixes"
      ],
      "examples": [
        {
          "text": "-kimbia (“to run”) + -zi → mkimbizi (“refugee”)",
          "type": "example"
        },
        {
          "text": "-teua (“to choose”) + -zi → uteuzi (“nomination”)",
          "type": "example"
        }
      ],
      "glosses": [
        "suffix used after a vowel in nominal forms of verbs, in conjunction with a noun class prefix"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "synonyms": [
    {
      "sense": "after a consonant",
      "word": "-i"
    }
  ],
  "word": "-zi"
}