Abstract: Stigma is a powerful force of social exclusion, yet the everyday communicative practices through which it is reproduced remain underexamined. This study investigates how stigma against people experiencing homelessness is embedded in ordinary discourse. We conducted a qualitative content analysis of UK Twitter posts (2019–2021) identified as stigmatising by individuals with lived experience of homelessness. Analysis revealed seven key bases of perceived differences upon which stigma of homelessness was constructed: appearance and hygiene, perceived deviant behaviour, dehumanisation, personal deficiency, social status, addiction and social undesirability. Crucially, stigma appeared not only in direct commentaries on homelessness but also in jokes, comparisons and casual remarks where homelessness was not the main topic. Based on this work, we theorise about the communicative architecture of stigma based on a shared system of symbolic shorthands and negative labelling of differences. We outline two key processes of Performative Invocation and Boundary Policing that reinforce stigma in everyday communication. Together, these dynamics contribute to the Passive Perpetuation of stigma, whereby negative meanings become socially accepted and embedded in common discourse. The paper highlights the fundamental role of communication in creating and perpetuating stigma and calls for greater attention to mundane communication as a site of community-level stigmatisation.