Subject is a synonym of Compel. Force is a type of Compel. 
Frequent is the opposite of Rare. Rare is related to Rabbit. Rabbit is related to Red. Red is related to Stop. 
Subject <--Synonym--> Compel <--IsA-- Force 
Frequent <--Antonym--> Rare <--RelatedTo--> Rabbit <--RelatedTo--> Red <--RelatedTo--> Stop 