Chapter 2 focuses on offensive language, positioned at the midpoint in the spectrum discussed in the first chapter. We situate offence and the acts of causing and taking offence in the theory of (im)politeness. The chapter reviews the development of (im)politeness theory through three waves and situates the current book within this theoretical progression. In this chapter, building on the previous literature, we also propose a model of offence which distinguishes between legal and moral (interactional) transgressions. To discuss the legal side, we focus on UK law, examining the challenges surrounding the concept of grossly offensive through a discussion of several high-profile cases. We also focus on moral-order transgressions which occur when interactional norms are breached. The chapter also argues that taking offence, whether face-to-face or online, could be a strategic social action used to, among other things, assert boundaries or influence social norms. As we argue, online offence may function as a tool for collective action, for raising awareness and for promoting social change.