Adjective used to describe someone that throws a hissy fit over every somewhat leaning negative thing you say towards them. It reminds you of when you sniff pepper and shake your nose irritably.
Scott: Im upset i can't go to Cross Country today. Its so much fun.
Cassidy: I just don't get how you can have fun in a sport where all you do is run, and run, ....and run!
Scott: I JUST DON'T UNDERSTAND WHY YOU CAN'T SHUT UP!
Cassidy: Jesus, you're extremely peppery today.