Dictionary use in secondary-school classics education in the Netherlands is problematic and an important cause of poor translations and text comprehension. Research on the topic is scarce and dictionary training plays a marginal role in the classics teaching practice. This explorative, qualitative think-aloud study examines which dictionary activities lead to success. We observed excellent secondary-school students while they were translating an Ancient Greek text. A feedback loop model, characterised as a slow process of constant verification, is used to analyse their dictionary behaviour. The findings show that successful dictionary activities depend on moving back and forth between text and dictionary, while the students reduce the cognitive load by activating schemata. Performing informed searches and using their fingers or the ribbon bookmark facilitate this process. In addition, closely monitoring the process with a critical mind, and linguistic reflection using appropriate metalanguage seem crucial.