Definist fallacy is a logical fallacy where someone uses a biased, misleading, or overly narrow definition of a term to unfairly influence or manipulate an argument. It involves defining a term in a way that distorts the meaning to support a particular conclusion, often deviating from its commonly accepted definition. The fallacy occurs when the chosen definition is intentionally different from the standard meaning, and its use obscures the true nature of the discussion, preventing genuine dialogue or critical examination.
For example, someone might say, "It's obvious that all protests are acts of violence because a protest is by definition any public gathering that disrupts normal activities." In this example, the speaker is committing the definist fallacy by using an overly narrow and biased definition of "protest" that focuses only on disruptions. This definition intentionally excludes peaceful protests or those without disruptions, thus misframing the term to unfairly label all protests as violent. By manipulating the definition, the argument distracts from the broader, more accepted understanding of protest as a form of expression, regardless of its impact on public order.