late at night

a night owl (idiomatic)

(euphemistic) job in the nightlife / sex industry

(Internet slang, humorous, pun) Christmas Eve, as a night of sexual activity between young couples

(collective, literally) a thousand nights / (archaic, figuratively, collective) lots of nights; an innumerable number of nights

a female given name

a surname / a surname

four things [small or without a counter category]

four months (duration)

万: ten thousand; a large number; all, everything