In this paper we throw further light on four questions on the argumentative use of emotive words studied in the recent literature on persuasive definitions. (1) What is the semantic and argumentative structure of an emotive word? (2) Why are emotive words so powerful when used as argumentative instruments? (3) Why and (4) under what conditions are persuasive definitions (based on emotive words) legitimate? After introducing leading accounts of the argumentative effects of words, we approach these questions from a pragmatic perspective, presenting an analysis of persuasive definition based on argumentation schemes. Persuasive definitions, we maintain, are persuasive because their goal is to modify the emotive meaning of a persuasive term in a way that contains an implicit argument from values. Our theory is also based on the concept of presupposition, often used in linguistics but here applied for the first time to these four questions about emotive words and persuasive definitions. © 2009 Elsevier B.V.