Dehumanisation is a central tool of propaganda, war and oppression, but could it also be an everyday phenomenon? This paper attempts to demonstrate that dehumanisation is not invariably deviant behaviour, but often grounded in normal cognition. Dehumanisation is often defined as to make less human (Encarta) or to deprive of human character (Oxford English Dictionary). Are these adequate definitions? Is there evidence of polysemy, and a more salient sense? How can we explain the meaning and enactment of this process? This paper investigates the linguistic and behavioural representation of dehumanisation, with reference to modern and historical events. This semantic analysis considers aspects of pragmatics, semiotics, cognition and metaphor. The framework used in this examination is the Natural Semantic Metalanguage method of Reductive Paraphrase (Wierzbicka & Goddard 2002; Wierzbicka 1972).