A person entrusted with the custody or care of something or someone; a caretaker or keeper.
a janitor; a cleaner
A designated internal mediator in an organization whose duty is to assist members with conflict resolution and other problems and to serve as an independent consultant to recommend changes to policies or procedures to improve organization effectiveness, efficiency, and humaneness.
An appointed official whose duty is to investigate complaints, generally on behalf of individuals such as consumers or taxpayers, against institutions such as companies and government departments.