I want to know what renunciation of scholarship mean? Is it the same as withdrawing from a scholarship program? Which one is better to quit a scholarship? Does renunciation of scholarship form enables a person to re apply to a scholarship again?
It will depend upon the specific rules of the funding agency and at what point you are renouncing the scholarship.
For example, I renounced a Ph.D grant from one agency before starting any further commitment because at the time of the results I already had received funding from another agency. In this case there was no drawback.
In Portugal you are able to renounce a Ph.D grant at latest 1 year after the start without penalties. However, after the first year if you renounce the grant and are not intending to finish the Ph.D the funding agency will demand the reimbursement of their investment on you.
For a more specific answer you should look at the rules of the particular scholarship that you have interest.