"Design anti-patterns are 'obvious, but wrong, solutions to recurring problems'."
Source: Software Design David Budgen.
"An AntiPattern is a pattern that tells how to go from a problem to a bad solution."
Source: C2 Wiki
"Recurring re-invented bad solutions to solve common problems."
Source: User Interface Anti Patterns Anders Toxboe. UI Patterns.
"Antipatterns are approaches to common problems that might appear obvious, but are less than optimal in practice.
When moving an organization toward good user experience practice, providing a documented—possibly extreme—example of bad practice as an antipattern can help raise awareness of what can go wrong and why we must avoid such bad practice. To effectively communicate a problem that we need to solve to an entire organization, we can write an antipattern in everyday, accessible language. In addition to sharing our understanding of a problem with a client, an antipattern also helps a UX team describe a solution for the problem. An antipattern lets a UX team present a solution in context, which helps people who aren’t UX specialists understand the pitfalls that are associated with a particular practice."
Source: "Antipatterns." Peter Hornsby. UX Matters.