sleepwaker noun2 •(no longer used, rare) A sleepwalker; one who walks in their sleep.He begins to speak, arises from his bed, walks about, and now becomes a sleepwaker. — 1860 •(no longer used) One in a state of magnetic or mesmeric sleep; someone in a hypnotic trance.I once asked a sleepwaker whether she could perceive any analogy between animal and mineral magnetism, when she replied, ' There is an analogy — but the latter is of a coarser nature.' — 1842 formssleepwakers