DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   bummer
       n 1: an experience that is irritating or frustrating or
            disappointing; "having to stand in line so long was a real
            bummer"
       2: a bad reaction to a hallucinogenic drug