Proscription

Proscription is a ’decree of condemnation to death or banishment’ ("Oxford English Dictionary").
It may refer to state-approved murder or banishment. The term originated in Ancient Rome, where a person could officially be declared an enemy of the state. It often involved confiscation of property. 
In addition to its use the Roman Republic, it has become a standard term. It has been used since to describe similar governmental and political actions. It is used to suppress opposing ideologies. Also, it is used to eliminate political rivals or personal enemies.