In a post on this word quite a while ago, it was said to be
obsolete. It seems a useful word, and I encountered it just
now in an introduction to some lectures about the schools of
Alexandria by Charles Kingsley.
"Least of all, perhaps, ought I to have presumed to publish them, as I have done, at Cambridge, where any inaccuracy or sciolism (and that such defects exist in these pages, I cannot but fear) would be instantly detected, and severely censured: but nevertheless, it seemed to me that Cambridge was the fittest place in which they could see the light, because to Cambridge I mainly owe what little right method or sound thought may be found in them, or indeed, in anything which I have ever written. "

And I found this in Carolyn's Corner:
Sciolism comes from the Late Latin sciolus, which means "smatterer" (or "one who speaks with spotty or superficial knowledge"). Sciolus comes from the diminutive of the Latin scius, meaning "knowing," which itself comes from the verb scire, meaning "to know." Of course, if you know something about Latin roots, you know that scire is the source of many other English words, including science, prescience ("foreknowledge"), nescience ("lack of knowledge"), and conscience.