Government by rich:

Solution (By Examveda Team)

The one word substitution is Plutocracy.

Oligarchy :a small group of people having control of a country or organization.
Aristocracy :a form of government in which power is held by the nobility.
Pantisocracy :a form of utopian social organization in which all are equal in social position and responsibility.
Plutocracy :government by the wealthy people.