Enemy is related to Friend. Friend is a synonym of Lover. 
Alive is related to Hill. Hill is related to Earth. Earth is related to Stuff. Stuff is related to Wave. 
Enemy <--RelatedTo--> Friend <--Synonym--> Lover 
Alive <--RelatedTo--> Hill <--RelatedTo--> Earth <--RelatedTo--> Stuff <--RelatedTo--> Wave 