You can use the endpoint to add a thesaurus entry with a user-specified ID to the thesaurus:

POST /gsadmin/v1/cloud/thesaurus/user_specified_id
{
  "ecr:type" : "thesaurus-entry",
  "type": "one-way",
  "synonyms": [
  "dig"
      ]
  "searchTerms": "digit"
}

You can use the endpoint to add a thesaurus entry with system-generated ID to the thesaurus:

POST /gsadmin/v1/cloud/thesaurus
{
  "ecr:type" : "thesaurus-entry",
  "type": "one-way",
  "synonyms": [
  "dig"
      ]
  "searchTerms": "digit"
}

Or you can use the endpoint to import thesaurus configuration in a zip file:

POST /gsadmin/v1/cloud/thesaurus