One who, while exhibiting the outward affectations of substance, worldliness & sophistication, is in fact a rank amateur with a fondness for plagiarism & convincing surfaces.
Of Scandinavian origin(akin to Icelandic klunni, clumsy person), or of Low German origin.
i thought i bloody well invented arse-clown, but i guess not. an arse-clown is someone who tools around and is a bit weak instead of getting the job done.
that bloke there with the side burns and the john lennon glasses, talking about how much he earns in the IT industry, my best guess is he's been an arseclown from the get-go.