A short person who feels inferior because of their size. They tend to take it out on other people and thrive on power trips. Shouting at others, especially when they are in a position of power, is common. Side affects include short temper, power trips/power-hungriness, anger issues, and often a bad sense of humor.
Mr. Weissman (Marjory Stoneman Douglas High School) has the biggest Napoleon Complex ever...well, almost. He's the perfect example. Ask any of his students.