Language Of Confusion: Pest

Brought to you my cat Bluey, who just scratched me. Because she’s a pest.

 
Pest showed up in the mid sixteenth century, a little after pester, which it seems to not be related to. It’s from the French peste, which means plague or pestilence, and its origin before that is unknown—though I want to add that pesky is actually thought to be related to pest, too. Then there’s pester, which is not related to pest and actually originally meant to clog or entangle, not meaning to annoy until a few decades later, probably because of the word pest. It’s short for the French empestrer, to put in an embarrassing situation, from the Vulgar Latin impastoriare, to hobble an animal, and that’s a mix of the prefix im-, meaning in, and the Medieval Latin phrase pastoria chorda, to rope an animal. In classical Latin, pastoria means pastoral, so like a pastoral animal, with a rope around it. And that’s pester.

 
And of course that’s where pastor, pasture, and pastoral come from. Pastor showed up in the late fourteenth century meaning a shepherd, and figuratively a minister. Pastoral showed up in the early fifteenth century, and pasture also from the fourteenth century. Pasture is from the Old French pasture, from the Late Latin pastura, and that’s from the classical Latin pastus, grazing, from the verb pascere, the origin for all of these words that means feed. That’s from the Proto Indo European pa-, to protect or feed, the origin for a bunch of other words I’ll have to etymologize at some point. Maybe next week.
 
The TL;DR here is that pest is probably not related to pester, and pester is related to pastoral. Because etymology.
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at Austin Linguistic Research Center
University of Texas at San Antonio’s page on Proto Indo European language
Dictionary of Medieval Latin
Encyclopaedia Britannica