som ‧ nam ‧ bu ‧ list /sɒmˈnæmbjələst, sɒmˈnæmbjʊləst $ sɑːm-/ BrE AmE noun [countable] formal
[ Date: 1700-1800 ; Language: Modern Latin ; Origin: somnambulus , from Latin somnus ( ⇨ ↑ somnolent ) + ambulare 'to walk' ]
someone who walks while they are asleep SYN sleepwalker
—somnambulism noun [uncountable]