Kill is related to Dead. Dead is related to Stick. Stick is the opposite of Automatic. Automatic is derived from Auto. 
Forget is related to Remember. Remember requires Still. 
Kill <--RelatedTo--> Dead <--RelatedTo--> Stick <--Antonym--> Automatic --DerivedFrom--> Auto 
Forget <--RelatedTo--> Remember --HasPrerequisite--> Still 