1) A b move is somethingdone by someone that is rather small but incredibly stupid of them. Sort of like the bonehead play of everyday life.
2) A brief moment of no common sense.
Guy 1: I don't know why I just spent 10 minutes getting dressed for the cold when we're about to smoke a cigarette in the warm car.
Guy 2: That such a b move.
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)