- Someone who walks about in their sleep.
1918, W. B. Maxwell, chapter 15, in The Mirror and the Lamp:
- Edward Churchill still attended to his work in a hopeless mechanical manner like a sleep-walker who walks safely on a well-known round. But his Roman collar galled him, his cossack stifled him, his biretta was as uncomfortable as a merry-andrew's cap and bells.
somnambulist — see somnambulist