First of all i would ask you to check the search from UI with both this search Criteria i.e *neele* and *neelesh* and check what is the result you are getting and if it is the same.
If the result varies i would suspect the issue may be with authentication.
When you are hitting the rest Service you must have authorized the service with admin account so you would be getting all the result which you may not be seeing using normal account.
So you need to pass the current user in header property X-Jive-Run-As before fetching the result.
Hope this helps.
Let me know in case of you are still facing the issue.
Thanks Samarth Like you mentioned we checked the search results form the site UI and could figured out why for neeles/neel/neelesh we are getting search results.
Jive search service searches for the keywords in the filter specified like in our case projects with the project name,creator,description and other informations.
So earlier what we just assumed it to match the project name but that's not the case.
Thanks for following us in community and providing solutions