I. NATURE OF IDEAS COMMUNICATED
[Nouns] unintelligibility; incomprehensibility, imperspicuity; inconceivableness, vagueness; obscurity; ambiguity [more]; doubtful meaning; uncertainty [more]; perplexity (confusion) [more]; spinosity; obscurum per obscurius; mystification (concealment) [more]; latency [more]; transcendentalism.
paradox; riddle, enigma, puzzle (secret) [more]; diagnus vindice nodus; sealed book; steganography, freemasonry.
pons asinorum, asses' bridge; high Dutch, Greek, Hebrew; jargon (unmeaning) [more].
[Verbs] be unintelligible; require explanation [more]; have a doubtful meaning, pass comprehension.
not understand [more]; lose, lose the clue; miss; not know what to make of, be able to make nothing of, give it up; not be able to account for, not be able to make either head or tail of; be at sea (uncertain) [more]; wonder [more]; see through a glass darkly (ignorance) [more].
not understand one another; play at cross purposes (misinterpret) [more].
[Adjectives] unintelligible, unaccountable, undecipherable, undiscoverable, unknowable, unfathomable; incognizable, inexplicable, inscrutable; inapprehensible, incomprehensible; insolvable, insoluble; impenetrable.
illegible, as Greek to one, unexplained, paradoxical; enigmatic, enigmatical, puzzling (secret) [more]; indecipherable.
indefinite (indistinct) [more]; perplexed (confused) [more]; undetermined, vague, loose, ambiguous; mysterious; mystic, mystical; acroamatic, acroamatical; metemphirical; transcendental; occult, recondite, abstruse, crabbed.
inconceivable, inconceptible; searchless; above comprehension, beyond comprehension, past comprehension; beyond one's depth; unconceived.
inexpressible, undefinable, incommunicable.