esoteric, unheard-of, ununderstood, little-known, obscure, unapprehended, nonunderstood, subtle, recondite, hidden, more...

common, known, familiar, ordinary

enchantment, divination, illusion, necromancy, transmutation, evocation, abjuration, conjuration, more...

little, such, more, first, unmarged, own, profound, certain

difficult words,   difficult word,   mysterious to most,   obscure things