[mys.te.ri.ous] adj (1600) 1 a: of, relating to, or constituting mystery "the ~ ways of God" b: exciting wonder, curiosity, or surprise while baffling efforts to comprehend or identify: mystifying "heard a ~ noise" "a ~ stranger"
2: stirred by or attracted to the inexplicable -- mys.te.ri.ous.ly adv -- mys.te.ri.ous.ness n