This is short for "Mouth Open, Mind Closed." It's used when dealing with people who constantly talk without listening. This trait is common amongst guidos. Customer service agents think it often when dealing with pushy, rude customers.
Dude 1: Say dude, wanna come to the party tonight?
Dude 2: I -
Dude 1 (interrupts): Great! I'll see you there!
Dude 2: But I can't go!
Dude 1: We're gonna have a great time there! That really hot blonde is gonna be there, and I'm counting on you to be my wing man!
Dude 2: Yuck, this dude is M.O.M.C.
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.