identicalness vs unity

identicalness and unity both are nouns.

Word	Noun	Adjective	Verb	Adverb
identicalness	Yes	No	No	No
unity	Yes	No	No	No

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

Other hyponyms of identicalness include oneness, selfsameness.

identicalness (noun)	unity (noun)
exact sameness	the quality of being united into one
	the smallest whole number or a numeral representing this number
	an undivided or unbroken completeness or totality with nothing wanting