Healthy is the opposite of Ill. Ill is related to Disease. Disease is related to Death. Death can be Tragic. 
Decade is related to Year. Year is related to Calendar. Calendar is a type of List. 
Healthy <--Antonym--> Ill <--RelatedTo--> Disease <--RelatedTo--> Death --HasProperty--> Tragic 
Decade <--RelatedTo--> Year <--RelatedTo--> Calendar --IsA--> List 