darkness vs night

darkness and night both are nouns.

Word	Noun	Adjective	Verb	Adverb
darkness	Yes	No	No	No
night	Yes	No	No	No

As nouns, night is a hyponym of darkness; that is, night is a word with a more specific, narrower meaning than darkness:

darkness (noun)	night (noun)
a swarthy complexion	darkness
having a dark or somber color	the time after sunset and before sunrise while it is dark outside
an unenlightened state	a period of ignorance or backwardness or gloom
an unilluminated area	the dark part of the diurnal cycle considered a time unit
absence of light or illumination	the time between sunset and midnight
absence of moral or spiritual values	the period spent sleeping
	a shortening of nightfall