Introduction Modern assessment in medical education is increasingly reliant on human judgement, as it is clear that quantitative scales have limitations in fully assessing registrars’ development of competence and providing them with meaningful feedback to assist learning. For this, possession of an expert vocabulary is essential.

Aim This study aims to explore how medical education experts voice their subjective judgements about learners and to what extent they are using clear, information-rich terminology (high-level semantic qualifiers); and to gain a better understanding of the experts’ language used in these subjective judgements.

Methods Six experienced medical educators from urban and rural environments were purposefully selected. Each educator reviewed a registrar clinical case analysis in a think out loud manner. The transcribed data were analyzed, codes were identified and ordered into themes. Analysis continued until saturation was reached.

Results Five themes with subthemes emerged. The main themes were: (1) Demonstration of expertise; (2) Personal credibility; (3) Professional credibility; (4) Using a predefined structure and (5) Relevance.

Discussion Analogous to what experienced clinicians do in clinical reasoning, experienced medical educators verbalize their judgements using high-level semantic qualifiers. In this study, we were able to unpack these. Although there may be individual variability in the exact words used, clear themes emerged. These findings can be used to develop a helpful shared narrative for educators in observation-based assessment. The provision of a rich, detailed narrative will also assist in providing clarity to registrar feedback with areas of weakness clearly articulated to improve learning and remediation.