IPA: /nɒkˈtæmbjʊlɪst/
KK: /nɑkˈtæmbəlɪst/
A person who walks during the night, often while asleep.
The noctambulist wandered through the quiet streets, unaware of his surroundings.
Noctambulist → It is formed from "noctis" (meaning night) and "ambulare" (meaning to walk). The word describes a person who walks at night, commonly known as a sleepwalker.
Think of someone 'walking' ('ambulare') during the 'night' ('noctis') — that's why a noctambulist is a person who walks at night.