ty|rant «TY ruhnt», noun.
1. a person who uses his power cruelly or unjustly; one who treats those under his control tyrannically; despot: »
A good teacher is never a tyrant. Necessity is the argument of tyrants; it is the creed of slaves (William Pitt).
2. a king or other ruler who uses his power unjustly or cruelly; despotical ruler; cruel master.
3. an absolute ruler, as in ancient Greece, who owed his office to usurpation. Some tyrants of Greek cities were mild and just.
Useful english dictionary. 2012.