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 1892 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 pure conjecture-no one knows for sure. (Merriam-Webster)