Unique is similar to Specific. Specific is related to Name. Name is the opposite of Anonymous. 
Mainstream is a type of Thought. Mainstream is related to Popular. Popular is related to Known. 
Unique <--SimilarTo--> Specific <--RelatedTo--> Name <--Antonym--> Anonymous 
Thought <--IsA-- Mainstream <--RelatedTo--> Popular <--RelatedTo--> Known 