Dictionary.net

/bliv'*t/ [allegedly from a World War II military term meaning"ten pounds of manure in a five-pound bag"] 1. An intractableproblem.2. A crucial piece of hardware that can't be fixed or replacedif it breaks.3. A tool that has been hacked over by so many incompetentprogrammers that it has become an unmaintainable tissue ofhacks.4. An out-of-control but unkillable development effort.5. An embarrassing bug that pops up during a customer demo.6. In the subjargon of computer security specialists, adenial-of-service attack performed by hogging limitedresources that have no access controls (for example, sharedspool space on a multi-user system).This term has other meanings in other technical cultures;among experimental physicists and hardware engineers ofvarious kinds it seems to mean any random object of unknownpurpose (similar to hackish use of frob). It has also beenused to describe an amusing trick-the-eye drawing resembling athree-pronged fork that appears to depict a three-dimensionalobject until one realises that the parts fit together in animpossible way.