desipient

Going through words starting with "de-" in the dictionary is depressing. They're all about losing or leaving: deforestation, defloration, deflation, deformation - that is until you find defenestration, which is still one of my favourite words (the act of flinging someone out of a window). Oh, er - and delight too I suppose. Yes, that's not a sad word. Anyway, here's a word that was new to me for today's choice:

desipient adj playing the fool; trifling - n desipience. [Origin from Latin desipiens, -entis, pr p of desipere, from de- (negative) and sapere to be wise] Chambers, 1998

I think I like it because it's such a formal word to use for something so bumbling. Suggested usage: Who is this desipient joskin?

FYI I almost picked datolite, which I misread as "a hydrated silicate of bacon and calcium". (It was boron.)