Passing underperformance in students is ubiquitous across health and social care educators and is intimately related to the subsequent welfare of patients: underperforming students may become underperforming practitioners. This paper aims to examine how medical educators construct passing underperformance through an analysis of their social act of explaining such behaviours in peer-group settings. Ten focus groups were conducted with 70 medical educators across two UK schools with different curricular/assessment styles (England, Scotland). A qualitative content analysis of how educators explained their behaviours of passing underperformance was undertaken using the psychological concepts of proximality and distalness according to: (1) Malle's F.Ex. coding framework for behavioural explanations, and (2) participants' use of pronouns. 149 explanations of passing underperformance were identified: 72 for participants' own behaviour, 77 for others' behaviour. When explaining their own behaviour, participants used the proximal pronoun I 37% (n = 27) of the time and the distancing pronouns "we/you" 51% (n = 37) of the time. More Causal History of Reasons (38%; n = 27) and Enabling Factors (29%; n = 21) than Reasons (33%; n = 24) were cited. A similar pattern was found for explaining others' behaviour. Thus, medical educators used linguistic form, explanation mode and informational content within peer-group discussions to distance themselves from intentionality for their action of passing underperformance and highlighted desirable characteristics of themselves and medical educators in general. Faculty development programmes should develop assessors' awareness of how implicit factors within their talk can legitimise a culture of passing underperformance and explore the steps for cultural change.