like·ness / ˈlīknis/ •
n. the fact or quality of being alike; resemblance: her likeness to him was astonishing a family likeness can be seen among all the boys. ∎ the semblance, guise, or outward appearance of: humans are described as being made in God's likeness. ∎ a portrait or representation: the only known likeness of Dorothy as a young woman.THE RIGHT WORD affinity, analogy, likeness, resemblance, similarity, similitude
Two sisters who are only a year apart in age and who are very similar to each other in terms of appearance and personality would be said to bear a likeness to one another.
Similarity applies to people or things that are merely somewhat alike ( there was a similarity between the two women, both of whom were raised in the Midwest), while resemblance suggests a similarity only in appearance or in superficial or external ways ( with their short hair and blue eyes, they bore a strong resemblance to each other).
Affinity adds to resemblance a natural kinship, temperamental sympathy, common experience, or some other relationship ( she has an affinity for young children).
Similitude is a more literary word meaning likeness or similarity in reference to abstract things ( a similitude of the truth).
An analogy is a comparison of things that are basically unlike but share certain attributes or circumstances ( he drew an analogy between the human heart and a bicycle pump).