What is an nimcompook?

A 'nincompoop' is, according to many googled online sources, a 'silly, stupid or foolish person.' The root meaning, or 'origin,' or 'etymology' of the Word is not really known (at least, not by anyone I could find in a short search :). However, for a really enjoyable journey into how Words came to be, go to the Take Our Word For It website see link

One theory is that is is a corruption of 'non compos mentis' - Latin for 'not of sound mind'.