From Longman Dictionary of Contemporary Englishsleepwalkersleep‧walk‧er /ˈsliːpˌwɔːkə $ -ˌwɒːkər/ noun [countable] SLEEPsomeone who walks while they are sleeping
Examples from the Corpus
sleepwalker• She looked stunned, almost like a sleepwalker.• She smiled wanly at Corbett and, like a sleepwalker, rose and left him.• Anna followed her like a sleepwalker, her arm limp in Liz's grasp.• He moved like a sleepwalker, almost beyond fear, invoking Grimes' memory.• Like a sleepwalker, she thought, and it occurred to her that she should step back inside and shake him awake.• Most of us are like sleepwalkers here, because we notice so little.• Presently the man-apes began to move forward, like sleepwalkers, toward the source of that compulsive sound.• I walked like some sleepwalker as he showed me empty rooms and a steep, stone-vaulted cellar. 