arcane

1 difficult for one of ordinary knowledge or intelligence to understand <grammatical rules that seem arcane to generations of students who were never taught grammar in the first place> Synonyms abstruse, profound, deep, esoteric, hermetic (also hermetical), reconditeRelated Words erudite, learned, scholarly; academic (also academical), pedantic; complex, complicated, hard; darkling, enigmatic (also enigmatical), inscrutable, mysterious, mystic, mystical, orphic, uncanny; impenetrable, incomprehensible, unfathomable, unintelligible; ambiguous, cryptic; unanswerable, unknowable; baffling, bewildering, confounding, confusing, disorienting, mystifying, perplexing, puzzlingNear Antonyms easy, facile, simple, straightforward; comprehensible, fathomable, intelligible, understandable; apparent, clear, clear-cut, distinct, evident, lucid, manifest, obvious, perspicuous, plain, transparentAntonyms shallow, superficial

2 having an often intentionally veiled or uncertain meaning <the rebate form uses arcane language, the only purpose of which seems to be to disqualify buyers from actually getting a rebate> Synonyms ambiguous, obscure, cryptic, dark, deep, Delphic, double-edged, elliptical (or elliptic), enigmatic (also enigmatical), equivocal, fuliginous, inscrutable, murky, mysterious, mystic, nebulous, occult, opaqueRelated Words abstruse, esoteric, recondite; cloaked, concealed, disguised, masked, shrouded; beclouded, bedimmed, befogged, clouded, cloudy, dim, faint, foggy, fuzzy, hazy, indistinct, indistinguishable, misty, muddy, obfuscatory, obnubilated, obscurant (or obscurantic), shaded, shadowlike, shadowy, sphinxlike; indefinite, inexact, inexplicit, noncommittal, questionable, unclear, uncertain, undefined, undetermined, vague; impenetrable, incomprehensible, indecipherable, inexplicable; eerie (also eery), uncanny, weird; impalpable, inappreciable, intangible, invisible; unanswerable, unknowable; baffling, bewildering, confounding, confusing, mystifying, perplexing, puzzling, unfathomable; circuitous, indirect, roundabout; complex, complicated, difficult, obtuseNear Antonyms comprehensible, fathomable, intelligible, knowable, legible, pellucid, understandable; bright, distinct, evident, self-evident, self-explanatory; certain, firm, strong, sure; defined, determined; direct, straightforward; definite, exact, explicit; appreciable, palpable, tangible, visible; blatant, patent, unmistakableAntonyms accessible, clear, nonambiguous, obvious, plain, unambiguous, unequivocal

3 being beyond one's powers to know, understand, or explain <my predecessor in this job obviously had his own arcane system for filing things, and so I haven't a clue as to where anything is> Synonyms mysterious, cryptic, deep, enigmatic (also enigmatical), impenetrable, inscrutable, mystic, occult, uncannyRelated Words dark, darkling, fuzzy, murky, obscure, shadowy, vague; ambiguous, equivocal; imponderable, incomprehensible, unfathomable, unintelligible, unsearchable; inexplicable, unaccountable, unexplainable; unanswerable, unknowable; metaphysical, mystical, numinous, supernatural; abstruse, esoteric, recondite; baffling, befuddling, bewildering, confounding, confusing, disorienting, mystifying, perplexing, puzzlingNear Antonyms fathomable, intelligible, understandable; apparent, clear, evident, manifest, obvious, open-and-shut, palpable, patent, perspicuous, plain, straightforward, transparent, unambiguous, unequivocal, unmistakable