A waiver is a document that relinquishes somebody's responsibility. A bond waiver is a document that "forgives" or "pardons" somebody from having to pay a bond (fianza). For example, if you have an inability to pay because you have low or no income, you can request a waiver so that you don't have to pay for something which would normally be your responsibility.
Does the word "renuncia" apply to such things as government fee waivers? For example, to file a form with the government, you must pay a certain amount of money. If you request a fee waiver, and the government grants the fee waiver to you, you no longer have to pay the filing fee.