A coup d'état is a sudden and illegal seizure of government power, typically executed by a small group, often including military leaders or political factions. The goal is to overthrow the existing government and replace it with a new authority, often without the consent of the general population. Coups can lead to significant political instability and conflict within a country. They may result in changes to leadership, governance structures, and policies, and can sometimes lead to civil unrest or international intervention, depending on the circumstances surrounding the coup and the reactions of other nations.