sameness vs identity

sameness and identity both are nouns.

Word	Noun	Adjective	Verb	Adverb
sameness	Yes	No	No	No
identity	Yes	No	No	No

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

Other hyponyms of sameness include identicalness, indistinguishability, similarity, equality.

sameness (noun)	identity (noun)
the quality of being alike	the distinct personality of an individual regarded as a persisting entity
the quality of wearisome constancy, routine, and lack of variety	exact sameness
	the individual characteristics by which a thing or person is recognized or known
	an operator that leaves unchanged the element on which it operates