a person who fits the profile of a perfect douchebag. Someone, who often in public places, makes an ass out of themselves and the people associating with them. Derived from the term douche, which is a total ass clown, and maximus, a roman term meaning to a great degree. so Douchemous Maximus would be a complete and total douche.
Thomas - "You know that douche bag Dennis?" Tim - "Yeah that guy is a total douchemous maximus ." Thomas - "yeah he is..."