Perfect is one of those words that is pronounced differently based on what form is used. When it’s an adjective, you say, “Gee, that first chapter is per-fect.” When it’s a verb, you go: “You need to per-fect that first chapter.” The former is also often used as an intensifier, a word that emphasizes the degree of another word. For example, “That first chapter is perfect crap.”
Can you tell what I’ve been working on lately?
Anyway, perfect the adjective was the first to be “born,” so to speak. It’s pretty old, too, having first appeared in the early 13th century from the Old French word parfit (which, by the way, is where the word parfait comes from). That word is from the classical Latin perfectus, the past participle of perficere, to complete, finish. Makes sense. Something is usually considered complete when it is perfect.
Divide perficere up and you get the prefix per-. As I’ve mentioned, it is from the Latin preposition per and means “by means of, during, as in.” In this case, per- means “completely.” The ficere part of the word is from facere, to perform or to do. Combine them together and you get “to do completely,” which as I said above, is considered perfect.
The verb perfect came later, in the fourteenth century. I haven’t found a reason for the difference in pronunciation, but I theorize that the change was to avoid confusion. And like any evolution, language kept the different pronunciations that people liked using.