Definitional arguments establish that something fits or doesn't fit a particular category by clarifying what that category means. Debates about whether an act is 'terrorism' or 'freedom fighting,' whether someone is 'qualified,' or whether work is 'art' all hinge on definition. Effective definitional arguments distinguish your definition from common misconceptions, establish criteria for the category, or show how something meets those criteria. Definitional arguments can shift the frame of an entire debate.
Choose a contested term relevant to your field or interests (e.g., 'leadership,' 'innovation,' 'success'). Research how others define it. Propose your own definition, explaining your criteria. Show examples of what fits and doesn't fit your definition. Consider why stakeholders might prefer different definitions.
Definitions are not neutral; all definitions involve choices about what matters. Another mistake is thinking there's one 'correct' definition; actually, competing definitions can be simultaneously valid in different contexts.
From your work on claim-evidence connection, you know that arguments require both a claim and support that genuinely connects to it. Definitional arguments add a layer of logical complexity: the claim itself depends on first establishing what a word or category *means*. Before you can argue that something is or isn't X, you need a shared, defensible account of what X is. That prior work of establishing the definition is not preliminary throat-clearing — it often is the argument.
Consider how much depends on definition in real disputes. Is waterboarding torture? The answer doesn't hinge on what happened — the physical facts are agreed upon. It hinges entirely on whether those facts meet the criteria for "torture." Is a $15 minimum wage good for workers? That depends partly on who counts as "workers" (all workers or workers-currently-employed?), what counts as "good" (higher wages or more employment?), and over what timeframe. These aren't evasions — they're the actual contested questions. Arguments from definition make this explicit.
The structure of a strong definitional argument has three moves. First, establish criteria: what properties must something have to qualify as X? These criteria can be drawn from legal definitions, philosophical analysis, commonsense usage, or the argument's own stipulated framework. Second, apply criteria: show that the case in question meets (or fails to meet) those criteria, using evidence and reasoning. Third, defend the definition itself against likely objections — especially the objection that your criteria are biased, too narrow, or too broad. This third move is where definitional arguments often break open into deeper disagreements about values.
The rhetorical power of definitional arguments is that they can reframe a debate entirely. If your opponent is arguing within a frame that assumes X means A, and you successfully argue that X actually means B, you've changed what counts as evidence and what counts as a win. The civil rights movement's argument that segregation violated American ideals of freedom was partly an argument about what "freedom" means — and winning that definitional argument was inseparable from winning the political argument. Learning to recognize when a dispute is fundamentally definitional — and to argue at that level rather than trading evidence within an unchallenged frame — is one of the most practically powerful skills in rhetoric.