A waiver is a voluntary agreement given by one party for a specific action to be taken by another party on their behalf, or an agreement by the person to cease performing a specific action in order to give a legal benefit to the other person. For instance within a court case, if two parties enter into mediation and draw up agreements, one party may concede to allow the other party full ownership over a specific property or asset; therefore, it would be said that the person issued a waiver against their interest in property or asset.
If a person is being interviewed by police, the police have to offer the suspect legal representation, but the suspect can waive their right to the same if they wish. In such a case, the police would be lifted from the legal requirement to wait until the suspect's legal representation arrived, before proceeeding with questioning the suspect.