Côte d’Ivoire· informal
caïman
Meaning
a pupil who works extremely hard
Elsewhere
bûcheur
Explanation
Elsewhere a caïman is the reptile, and at the École normale supérieure it is the tutor who drills students. In Côte d'Ivoire it is the pupil who never looks up from the books.
Example
Elle est devenue un vrai caïman depuis qu’elle prépare le bac.
She's turned into a proper swot since she started revising for the bac.
Origin
From the Spanish caimán, probably borrowed from a Caribbean language, first recorded in French in 1530.
Source