An extreme mental and physical disorder, the chief symptoms of which are delusions of grandeur, extremely low intelligence and stunted growth. It is incurable and thankfully very rare.
Doctor: "I'm sorry, your son has been diagnosed with Stupid Haynus Syndrome. You may wish to consider putting him up for adoption"
The act (usually intentional) of leaving a smear of feces in one's underwear which is then disovered at a later date by the one who is laundering the fouled item. The discovery of such matter is so disgusting, it is considered a crime against humanity.
Every time I do my sons laundry, I discover that he has committed ANOTHER hanus crime by allowing his underwear to complete the wiping of his butt rather than performing it correctly with toilet paper.
This is a term which generally describes a badly looked after rectum. A hanus anus could be poorly wiped after defication, it may have hemorrhoids or a rash. In some of the worst cases a hanus anus can smell like a repugnant mix of shit and blood.
Those who do not bath frequently or have problems identifying what constitutes a clean asshole after shitting are generally susceptible to having a Hanus Anus.