ass clown (ás kloun) n.:

one, who, through the fault of his parents conception, is a skid mark in society's collective underwear.

1. One whose stupidity and/or ineptitude exceeds the descriptive potential of both the terms ass and clown in isolation, and in so doing demands to be referred to as the conjugate of the two. 2. A male who engages in homosexual behaviors. See butthole surfer

A person who by ignorance or stupidity takes up unnecessary amounts of your time.

A person whose stupidity and incompetence are magnified by their laziness and indifference.

A prick, who is at the same time a jackass.

A person who knows absolutly nothing about his job or trade but can tell everyone else how to do it better!!

an unmitigated fool or jerk; a sad sack; a tool or goof.