It's a word you give to a person if he/she wants to take revenge on things that are goverment-based and illy run. a male hopai's roar is defined by a loud M16 like sound, which is likely to frighten away cool-minded little roachers when they least expect it (or when they're acting "cool").
A Hopai's prey is little lump-legged rap-loving third formers. Hopai's natural enermy is a Mrs. Burrows. She shoots sharp lawsuit papers out of her anus to catch her prey. Unfortunaly when it comes to catching a Hopai there's hardly any success, as the Hopai is very fast.
There has only been one Hopai that has ever existed. He goes by the code-name "Lance" or "Hopai".