alikeness vs similarity

alikeness and similarity both are nouns.

Word	Noun	Adjective	Verb	Adverb
alikeness	Yes	No	No	No
similarity	Yes	No	No	No

As nouns, similarity is a hypernym of alikeness; that is, similarity is a word with a broader meaning than alikeness:

alikeness: similarity in appearance or character or nature between persons or things
similarity: the quality of being similar

alikeness (noun)	similarity (noun)
similarity in appearance or character or nature between persons or things	the quality of being similar
	a Gestalt principle of organization holding that (other things being equal) parts of a stimulus field that are similar to each other tend to be perceived as belonging together as a unit