A more thorough explanation:

Definition: A deputy is a person who is appointed or delegated to act as a substitute for another person, especially for an official.

For example, a deputy clerk is a person who is assigned to a particular courtroom or judge to assist with administrative tasks. A general deputy is a person who is appointed to act in another officer's place and execute all ordinary functions of the office. A special deputy is a person who is specially appointed to serve a particular purpose, such as keeping the peace during a riot.

These examples illustrate how a deputy is someone who is authorized to act on behalf of another person or official, and is given specific duties and responsibilities to carry out.