Fucktard's a good insult. Satisfying sound and a cool compound word.
Sorry to burst a few bubbles, but I'm 90% certain that most of the factoids on here are just cool colourful stories. Most of the better English swear words are derived from Anglo-Saxon words. Fuck didn't come from Fornication Under the King (or For Unlawful Carnal Knowledge which is another tempting version) and if there was ever a Goddess called Cunt I've never come across her (if you'll forgive the expression). I wrote an article on swear words some time ago and if my memory serves me right they were most likely derived from comparisons with objects in Old English. There must surely be a good site on this someplace, but as I can't post attachments I won't bother looking. If anyone finds one and proves me wrong, I shall eat an appropriate slice of humble pie.
Similarly sadly the finger-bowman story is just a colourful invention. It's usually applied to the English equivalent of the finger - 'flicking the V' - index and middle finger extended. There's no historical record of such a punishment being meted out to English bowmen by the French. If you were worth ransoming (unlikely if a bowman) then they'd sell you back in one piece, otherwise they'd just kill you. They didn't fuck about in the Hundred Years War. More likely, the sign's another anatomical reference. The 'V' resembled a woman's spread legs, while 'the finger' signified a dick, and was also the digit women most frequently used for masturbation.
Anyone know any better?