fairness vs justness

fairness and justness both are nouns.

Word	Noun	Adjective	Verb	Adverb
fairness	Yes	No	No	No
justness	Yes	No	No	No

As nouns, justness is a hypernym of fairness; that is, justness is a word with a broader meaning than fairness:

Other hypernyms of fairness include justice.

fairness (noun)	justness (noun)
conformity with rules or standards	the quality of being just or fair
the property of having a naturally light complexion	conformity with some esthetic standard of correctness or propriety
the quality of being good looking and attractive
ability to make judgments free from discrimination or dishonesty