somnambulist
From Longman Dictionary of Contemporary Englishsomnambulistsom‧nam‧bu‧list /sɒmˈnæmbjəlɪst $ sɑːm-/ noun [countable] formal SLEEPsomeone who walks while they are asleep SYN sleepwalker —somnambulism noun [uncountable]Examples from the Corpussomnambulist• The husband agreed that he had been bewitched; he spoke like a somnambulist, in tones of grief.Origin somnambulist (1700-1800) Modern Latin somnambulus, from Latin somnus ( → SOMNOLENT) + ambulare “to walk”