Answer: Synonym = Similarity
Step-by-step explanation:
A synonym is a word that is similar to another word by nature, this does not mean they are exact, but they share or express a common meaning.
Heres an example:
"These shoes are different."
"You have a unique style of hair."
The words are: Unique and different.
Although they do essentially mean the common phrase of difference, they are better off in their respective contexts, and in some cases, can be used interchangeably - one word substituting for another.