Erin McKean, for the New York Times:
Scholars recently analyzed more than five million digitized books, about 4 percent of all the books ever printed. Publishing their findings in “Science,” the researchers discovered that, by their estimation, “52 percent of the English lexicon – the majority of the words used in English books – consists of lexical ‘dark matter’ undocumented in standard references.”
I have something of a habit of using perfectly cromulent words like these occasionally to catch the reader off guard. But, as this eleven year-old article (also from the NY Times) summarizes, it’s best not to make writing sound like a writing exercise.