injustice vs unfairness

injustice and unfairness both are nouns.

Word	Noun	Adjective	Verb	Adverb
injustice	Yes	No	No	No
unfairness	Yes	No	No	No

As nouns, injustice and unfairness are synonyms defined as:

Other synonyms of injustice include iniquity, shabbiness.

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

Other hyponyms of injustice include inequity, wrong, wrongfulness.

injustice (noun)	unfairness (noun)
an unjust act	an unjust act
the practice of being unjust or unfair	injustice by virtue of not conforming with rules or standards
	partiality that is not fair or equitable