The Jargon File (version 4.4.7, 29 Dec 2003):

adger
 /aj'r/, vt.

    [UCLA mutant of nadger, poss. also from the middle name of an infamous 
    tenured graduate student] To make a bonehead move with consequences that
    could have been foreseen with even slight mental effort. E.g., ?He started
    removing files and promptly adgered the whole project?. Compare dumbass
    attack.