MYSTERIOUS

adj. 1 puzzling, enigmatic, baffling, insoluble, unsolvable, bewildering, confounding, confusing, perplexing, mystifying, weird, bizarre, strange, uncanny, curious A mysterious force makes the saucer rise off the ground and fly at incredible speeds 2 cryptic, arcane, secret, inscrutable, covert, hidden, furtive, unclear, dark, concealed, occult, inexplicable, incomprehensible, mystic(al), unknown, unfathomable, mystical, recondite, abstruse It is mysterious how the agency accomplishes its ends