A Tyrant person is a person of authority who basically abuses their power to assert their authority.
For example a police officer could try to say they can arrest someone for something they are doing even though it may not be against the law.
That police officer would be a tyrant because they are trying to abuse their power and think just because they have police powers that everyone must do what they say.
However just because someone is a police officer does not mean they always have authority over you.
A police officer has no authority over you until you actually commit a crime or have been suspected of a crime.
A police officer cannot just boss you around whenever they want too.
If the Police officer always tries to be a boss and demand you do things that they tell you when you're doing nothing wrong then that police officer is a tyrant.
A Tyrant is a person in a position of authority who exercises power oppressively or despotically.