A mash-up of the words "celebrity" and "retarded," the word celebutard refers to any of a crop of famous people (mostly young, mostly filthy rich) who are unable to form complete sentences in a public setting. In fact, they probably couldn't even grasp the concept that "celebutard" is made up of two separate words.
Did you see Paris/Jessica/Britney/Lindsey's interview in OK! Magazine? I was amazed at her erudition. Sike! She was a total celebutard.