Definition
Topicality is a procedural argument, most common in policy debate, that the opposing team's plan or case does not actually fall within the bounds of the stated resolution. It does not engage the substance of whether the plan is a good idea; it argues the plan should not be evaluated at all because it is not a legitimate interpretation of what the resolution permits.
Example
A resolution calls for increasing "environmental protection" policy. An affirmative team proposes a plan focused entirely on workplace safety regulation with no environmental component. A topicality argument would claim that workplace safety, however good a policy it might be, is not a topical example of environmental protection, and the round should not evaluate a plan outside the resolution's scope.
Common mistakes
Topicality is easy to raise reflexively whenever an opponent's case feels unfamiliar or hard to answer, which is a misuse of the argument. A well-run topicality argument needs its own standards: a clear interpretation of the contested term, a violation showing the opposing case does not meet it, and reasons that interpretation produces better debates. Raised without those pieces, it reads as a stalling tactic rather than a real procedural objection.