In property law, the act of wrongfully excluding someone, especially a cotenant, from real property. Acts such as changing the locks, posting �no trespassing� signs, or physically denying a cotenant admittance to a piece of property are all considered ousters. (Ousters of a notorious an unequivocal nature are often prerequisites for adverse possession.)
Unseating someone, especially a corporate or public official, from a position of power.
An �ouster clause,� which is sometimes referred to as a �privative clause,� is a clause in a piece of legislation that limits or wholly precludes judicial review. Though not a feature of the American legal system, ouster clauses are a part of other common law legal systems, such as those in the United Kingdom and its former colonies.