imperspicuus
From LSJ
τοῖς οἰκείοις βουλεύμασιν ἁλίσκεσθαι → hoist by one's own petard, hoist with one's own petard, hoist on one's own petard, hoisted by one's own petard, be hoist with one's own petard
Latin > English (Lewis & Short)
imperspĭcŭus: (inp-), a, um, adj. 2. in-perspicuus,
I not clear, obscure: judicum ingenia, Plin. Ep. 1, 20, 17.
Latin > French (Gaffiot 2016)
imperspĭcŭus,¹⁶ a, um, impénétrable : Plin. Min. Ep. 1, 20, 17.