A lower cost facsimile of true men's formal wear made by putting together a regular suit with a cummerbund, bow tie and pleated shirt.
Dave was going on a cruise that had 2 formal dinners. He dind't own a tuxedo and the cost of the cruise set him back a bunch. To avoid renting or buying real formal wear he bought a nice shirt, and a cummerbund and bow-tie set. It cost him much less than formal wear and made a reasonable faxedo for the affairs.
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.