When two people go in for a handshake and one person puts up knuckles and the other person goes for a standard handshake. A fucked up handshake or a fucked up attempt at one.
The boss went to shake my hand and I gave him knuckles on accident. What a knucklefuckle.
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.