A mess up, a mistake. You are said to have drebbed if you mess up like Frank Drebbin of 'Police Squad' fame. Invented by Matt Collings, who was a drebber himself, of the first degree.
A device was also formatted to measure these drebs; the drebbommitter.
Ha! look at you! you have drebbed up there! (Dinner all down front).
"oh I just drebbed!" (stepped in dogshit, etc)