An interjection that typically follows an extreme blunder in your stock portfolio, often due to following the advice of fellow retards in r/WallStreetBets
The exclamation of surprise and astonishment uttered by one who unexpectedly has an apple--or other firm-fleshed variety of pome or drupe--forcefully jammed into his or her open mouth.
Tripping over the curbstone hurt my pride a little, and my toes not at all, but the last thing I wanted to do at that moment was to jam a large crabapple into Summer Bletchfield's patrician tonsils; her irate, accusatory expostulation of "GUH!" will haunt my sleepless dreams through decades of agonizing regret.