noun

somnambulism

sahm-NAM-byuh-liz-um/sɑːmˈnæmbjəlɪzəm/

The condition or practice of walking while asleep.

An adult with somnambulism walks away from bed while still asleep.

An adult in ordinary pajamas walks quietly from a bed into a clear safe room while still asleep, eyes open with unfocused gaze and arms resting naturally; small moon in window indicates night, no zombie pose, dreamwalking claim or dangerous stairs.

Etymology

somnLatinsleep

+ambulLatinto walk

+ismFrenchcondition or practice

Sleep and walking combine literally here: the underlying compound named a sleepwalker. The ending makes it the condition or practice, rather than the person who walks while asleep.

More examples

She has no memory of her episodes of somnambulism.
Somnambulism is more common in children than in adults.
The doctor asks whether somnambulism runs in his family.

Forms

somnambulism

somnambulist noun — A person who walks while asleep.

somnambulistic adjective — Relating to walking while asleep.

Similar words

sleepwalking: The everyday term for the same condition or behavior.