Answer
There isn't really a "clean-cut" definition out there just yet, unlike Design Patterns. Basically, as Design Patterns (and more particularly, Process Patterns) try to codify a standard vocabulary for working solutions to problems that reappear frequently, Anti-Patterns represent an effort to define and classify reoccuring non-solutions, i.e., things that lots of projects do that fail to yield a solution, or actually prevent a project from working or being finished.
The most basic example I can think of is "The Hammer", inspired by the old addage, "If your only tool is a hammer, everything looks like a nail" (or the variation, "If your only tool is a hammer, everything looks like your left thumb." Hammer describes a regular, reoccuring problem in inexperienced engineers (particularly those who've only used one language for the bulk of their carreer so far), that of trying to force-feed all problems into the solutions they already know.
http://www.antipatterns.com/ has more information.
yes, there're lots of points which are worthwhile to do a research on...
1.clean-cut, as an adj, like "clear"
2.out there
3. inspired by the old addage here the addage may be wrong, adage should be the right one
4.for the bulk of
5.force-feed