somnambulism vs sleeping

somnambulism and sleeping both are nouns.

Word	Noun	Adjective	Verb	Adverb
somnambulism	Yes	No	No	No
sleeping	Yes	Yes	No	No

As nouns, sleeping is a hypernym of somnambulism; that is, sleeping is a word with a broader meaning than somnambulism:

Other hypernyms of somnambulism include walk, walking.

somnambulism (noun)	sleeping (noun)
walking by a person who is asleep	the suspension of consciousness and decrease in metabolic rate
	quiet and inactive restfulness
	the state of being asleep

somnambulism (adjective)	sleeping (adjective)
	lying with head on paws as if sleeping