Persnickety people like things neat and tidy, but the etymology of persnickety doesn't provide the kind of clean, clear explanation that appeals to the fastidious. Persnickety was first documented in English in the late 19th century as an alteration of pernickety, a word that has the same meaning. Pernickety goes back to the early 1800s, but from there, the word's history gets messy. Some say pernickety might be from a child's version of particular; others, that the nick part came from association with knick-knack. Or perhaps the Latin prefix per-, meaning "thoroughly," played a role. But it's all conjecture-no one knows for sure.