The worst insult anyone could call you. It's meaning is something unspeakable, even in this eternal hellhole that is the internet. It's not even considered a slur, which only makes it worse, as the person saying it doesn't even consider you worth enough to sacrifice their profesionality just to insult you.
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.