blivet
/bliv'*t/ [allegedly from a World War II military term
meaning "ten pounds of manure in a five-pound bag"] n. 1. An
intractable problem. 2. A crucial piece of hardware that can't be
fixed or replaced if it breaks. 3. A tool that has been hacked
over by so many incompetent programmers that it has become an
unmaintainable tissue of hacks. 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, a denial-of-service attack performed by hogging
limited resources that have no access controls (for example, shared
spool space on a multi-user system).
This term has other meanings in other technical cultures; among
experimental physicists and hardware engineers of various kinds it
seems to mean any random object of unknown purpose (similar to
hackish use of frob). It has also been used to describe an
amusing trick-the-eye drawing resembling a three-pronged fork that
appears to depict a three-dimensional object until one realizes
that the parts fit together in an impossible way.