Chekism is a term that relates to the situation in the Soviet Union where the secret police strongly controlled all spheres of society. It is also used to point out similar circumstances in post-Soviet intelligence states such as modern Russia. The term can refer to the system of rule itself, and to the underlying ideology that promotes and popularizes political police violence and arbitrariness against real and imagined enemies of the state.

Secret police are police, intelligence, or security agencies that engage in covert operations against a government's political, religious, or social opponents and dissidents. Secret police organizations are characteristic of authoritarian and totalitarian regimes. They protect the political power of a dictator or regime and often operate outside the law to repress dissidents and weaken political opposition, frequently using violence. They may enjoy legal sanction to hold and charge suspects without ever identifying their organization.