undetricesimus
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
Latin > English (Lewis & Short)
undētrīcēsĭmus: or undētrīgē-sĭmus, a, um, num. adj. id.,
I the twentyninth: dies, Liv. 25, 36, 14: in commentariorum undetricesimo, Gell. 10, 5, 1.
Latin > French (Gaffiot 2016)
ūndētrīcēsĭmus¹⁶ (-trīge-), a, um, vingt- neuvième : Liv. 25, 36, 14 ; Gell. 10, 5, 1.