Sack is the opposite of Hire. Hire is a synonym of Rental. Rental is related to Library. 
King is related to People. People is a type of Family. Family is related to Structure. Structure is a type of Constitution. 
Sack <--Antonym--> Hire <--Synonym--> Rental <--RelatedTo--> Library 
King <--RelatedTo--> People --IsA--> Family <--RelatedTo--> Structure --IsA--> Constitution 