refractarius
From LSJ
Ἔοικα γοῦν τούτου γε σμικρῷ τινι αὐτῷ τούτῳ σοφώτερος εἶναι, ὅτι ἃ μὴ οἶδα οὐδὲ οἴομαι εἰδέναι → I seem, then, in just this little thing to be wiser than this man at any rate, that what I do not know I do not think I know either
Latin > English (Lewis & Short)
rē̆fractārĭus: a, um, adj. refringo,
I stubborn, obstinate, refractory: contumaces ac refractarios, Sen. Ep. 73, 1.