A fear that you might be on mute or unmute on your computer during a work audio or video conference, and unintentionally be heard when you are indulging in an unrelated activity, or not heard when you are trying to speak and everyone seems to be ignoring you, and might cause the act of repeatedly checking the mute button.
A word coined on the TV show "The Prisoner." Main character Number Six was once declared "unmutual and disharmonious" for not obeying the rules and for not honoring his obligations as a "citizen" of The Village, his prison. In other words, an "unmutual" was a bad member of the Village society because he was a disruptive influence, refusing to join in or play by the rules.
To be classed as an unmutual meant a citizen would be shunned by other citizens until he conformed or became "mutual." If that didn't work, other citizens would eventually take it upon themselves to correct the unmutual's behavior with increasing levels of violence.
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.