To leave a party or other social gathering without being detected. Usually the other participants do not realize the departure until some time later. black-fogs, black-fogging, black-fogged
Origin: "black fog", something never seen
-"Hey, where's Bill?"
-"I dunno... what, did he leave?"
-"Looks like he black-fogged!"
"Brian got caught last night trying to black-fog. He's usually really good at it, but Carrie saw him walking to his car."
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)