Bullet is related to Fast. Fast is the opposite of Weak. Weak is a synonym of Thin. 
Stone is a type of Kill. Stone is related to Coal. Coal is related to Hard. 
Bullet <--RelatedTo--> Fast <--Antonym--> Weak <--Synonym--> Thin 
Kill <--IsA-- Stone <--RelatedTo--> Coal <--RelatedTo--> Hard 