puzzling
abstruse, ambiguous, baffling, bewildering, beyond one, enigmatic, full of surprises, hard, incomprehensible, inexplicable, involved, knotty, labyrinthine, misleading, mystifying, oracular, perplexing, unaccountable, unclear, unfathomable
Antonyms
clear, comprehensible, easy, evident, intelligible, lucid, manifest, obvious, patent, plain, simple, unambiguous, unequivocal, unmistakable