Monarchy
Part of speech: noun
Definition: A government with a hereditary head of state (whether as a figurehead or as a powerful ruler).
Example sentence: I've spent a bit of time with the Prince of Wales, who I respect greatly. I'd give two cheers for the Monarchy.
Tyranny
Part of speech: noun
Definition: A government in which a single ruler (a tyrant) has absolute power.The office or jurisdiction of an absolute ruler.Absolute power, or its use.Extreme severity or rigour.