An amnesty is a treaty signed by a sovereign state that grants a person/people forgiveness for all their crimes.
In Nilfgaard, when an Imperator ends his reign, his successor usually grants amnesty to all sentenced under the previous ruler. According to Nilfgaardian laws, however, those accused of high treason against the state aren't allowed to receive forgiveness, like in the case of Vysogota of Corvo, with the amnesty proclaimed by the Usurper and later denied by Emhyr var Emreis.[1]
Emperor Emhyr also planned to grant another amnesty after his marriage with Cirilla of Cintra.[1]