What counts as disinformation for everyday citizens? While research often focuses on detection and correction, lay people’s everyday understandings and applications of this concept remain underexplored. Drawing on open-ended survey responses (N = 91) and interviews with UK citizens (N = 20), this study combines Reflexive Thematic Analysis and Discursive-Rhetorical Psychology to examine lay representations and argumentative uses of the term “disinformation”. Results show that citizens commonly anchor “disinformation” within social media, politics, and health, often linking it to specific figures (e.g., Trump), profiles (“conspiracy believers”), or events (COVID-19; Brexit, etc.). They distinguish between blatant and subtle forms and discuss its importance vis-à-vis other social issues. Regarding disinformation’s rhetorical functions, participants tend to distance themselves from those deemed vulnerable to misleading information. Susceptibility is usually framed in individualized terms, such as age, education, or gullibility, invoking the widespread idea that everyone should “do their own research”. Some participants, however, represent vulnerability as socially produced, rooted in media infrastructures or broader social-psychological processes, including loneliness and weakened community ties. These findings show how “disinformation” has become a rhetorical tool shaping everyday identity and collective sense-making, offering new ways to address the societal and psychological effects of epistemically polluted media environments and their consequences for scientific and democratic institutions.