I've always been interested in the morphology and etymology of words, and often fantasise outlandish origins or amusing back-formations of my own for them.
One of the first words I remember becoming slightly obsessed with - when I was only about 10 or 12 years old - was preposterous.
The prefix I understood, but there was something very odd-looking about posterous. It seemed to me that it ought to have something to do with posters. In fact, I soon convinced myself that it ought to mean worthy of being celebrated on a poster (not necessarily the same thing as appearing on a lot of posters, you understand: it's the difference between Gandhi or Einstein and Justin Bieber or David Beckham).
Hence, when you're on your way to global fame but you haven't quite got there yet, you're pre-posterous. And soon enough, of course, the hyphen falls away - et voilà!
Well, I think it ought to be a word.
Footnote 1: I have learned that Posterous - with a tie-in to a rather different idea of 'post' and 'posters' - was adopted a few years ago as the name for a mobile blogging platform.
Footnote 2: Preposterous is ostensibly derived from Latin (the logically strained combination of 'pre-' and 'post' implying back-to-front or topsy-turvy), but it looks like late medieval cod-Latin to me; I'm pretty sure I never came across praeposterus anywhere in the Classical canon!