- a government official who hears and investigates complaints by private citizens against other officials or government agencies.
- a person who investigates and attempts to resolve complaints and problems, as between employees and an employer or between students and a university.
- a commissioner who acts as independent referee between individual citizens and their government or its administration
- (in Britain) an official, without power of sanction or mechanism of appeal, who investigates complaints of maladministration by members of the public against national or local government or its servants
