Fisherman is related to Catch. Catch is the opposite of Garbage. Refuse is a type of Garbage. 
Silk is related to Insect. Shark is a type of Insect. Shark is a type of Cheat. 
Fisherman <--RelatedTo--> Catch <--Antonym--> Garbage <--IsA-- Refuse 
Silk <--RelatedTo--> Insect <--IsA-- Shark --IsA--> Cheat 