I'd like to add liar, as well. Someone who is not a native English speaker who uses a colloquial phrase like "whackjob" correctly probably doesn't have the mangled English you aspire to write. Either that, or the Americans you hang out with online routinely apply the word to you, perhaps for thinking hanging out with them in a forum makes you more American than being born and residing in Germany makes you German, in which case we can conclude that you are a nutter.