To hide or sleep during the day and come out or travel at night; often used to describe avoiding being seen or caught.

nocturnality; occurring or active at night

Literally meaning to wear fine silk clothes in the dark of night; used to describe having wealth or success that no one knows about, or not having one's achievements properly recognized.

(idiom) to travel or march under cover of night and remain hidden during the daylight hours

a march conducted by troops during the night

to wear fine embroidered clothes while walking in the dark; to have achieved great success or wealth without others knowing about it

Night travelers, specifically thieves or knights-errant who move about secretly at night.