To be unpleased by an event, which leaves with a certain amount of insatisfaction for the rest of your day.
I was supposed to go on a date with this amazing girl tomorrow, she cancelled because she had too much work to do. I am so off. That's probably the best definition of "to be off", since you're really excited, but get taken your fun away suddenly.
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.
We have a Zoom meeting in a few minutes and I’ll probably go pajama casual.