"Our company experienced a Brobdingnagian increase in revenue last quarter."
Brobdingnagian? Is Brobdingnagian even an English word? Yes, it is! It means gigantic or massive. Should you use it? Probably never! Why? English has the largest vocabulary in the world. The problem becomes that English students will learn words like these and then want to use them to impress others with their vocabulary. This becomes a big problem when others do not understand them, including 99% of native English speakers. Don't allow your English to become arrogant as it becomes great. Learn to use it so others can better understand what you want to communicate.