Key is related to Item. Item is related to Chair. Chair is etymologically related to Settle. Settle is the opposite of Remove. 
Sign is related to Short. Shorts is a form of Short. 
Key <--RelatedTo--> Item <--RelatedTo--> Chair --EtymologicallyRelatedTo--> Settle <--Antonym--> Remove 
Sign <--RelatedTo--> Short <--FormOf-- Shorts 