day vs dark

day and dark both are nouns.

Word	Noun	Adjective	Verb	Adverb
day	Yes	No	No	No
dark	Yes	Yes	No	No

day (noun)	dark (noun)
a period of opportunity	an unenlightened state
time for Earth to make a complete rotation on its axis	an unilluminated area
a day assigned to a particular purpose or observance	absence of light or illumination
the time after sunrise and before sunset while it is light outside	absence of moral or spiritual values
a point or period in time	the time after sunset and before sunrise while it is dark outside
the recurring hours when you are not sleeping (especially those when you are working)
an era of existence or influence
the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day
the period of time taken by a particular planet (e.g. Mars) to make a complete rotation on its axis

day (adjective)	dark (adjective)
	devoid of or deficient in light or brightness; shadowed or black
	(used of color) having a dark hue
	brunet (used of hair or skin or eyes)
	secret
	causing dejection
	stemming from evil characteristics or forces; wicked or dishonorable
	showing a brooding ill humor
	not giving performances; closed
	marked by difficulty of style or expression
	lacking enlightenment or knowledge or culture