abscons

so abstruse as to prevent comprehension entirely

“Je ne veux rien savoir du chagrin, de l'amour, de l'ennui, je ne veux rien savoir de ces choses-là, de tout ce fatras ordinaire et abscons.”

Borrowed from Latin abscōnsus. First attested in a translation dated to 1478 of a medical book in Latin written in 1363 (Guy de Chauliac's Inventarium sive chirurgia magna). Related to Old French abscondre, which it eclipsed in usage while being its participle, and Old French escondre.