Competitor is a synonym of Opponent. Opponent is a synonym of Opposition. Opposition is related to Question. Question is related to Unique. 
Individual is the opposite of Joint. Joint is related to Connect. 
Competitor <--Synonym--> Opponent <--Synonym--> Opposition <--RelatedTo--> Question <--RelatedTo--> Unique 
Individual <--Antonym--> Joint <--RelatedTo--> Connect 