Classical allusions, poetical turns of phrase, antique diction, recondite words.
How else to explain the popularity of a novel so free of plot, so obsessed with existential rumination and recondite philosophy?
1640s, "removed or hidden from view," from Old French recondit, from Latin reconditus, past participle of recondere "store away, hide, conceal, put back again, put up again, lay up," from re- "away, back" (see re-) + condere "to store, hide, put together," from con- "together" (see con-) + -dere "to put, place," comb. form of dare "to give" (see date (n.1)). Meaning "removed from ordinary understanding, profound" is from 1650s; of writers or sources, "obscure," it is recorded from 1817.