Spy is related to Mystery. Mystery is the opposite of Known. Known is the opposite of Unknown. Unknown is related to Experiment. 
Contractor is derived from Contract. Contract is a synonym of Take. Take is a type of Use. Use is a synonym of Occupy. 
Spy <--RelatedTo--> Mystery <--Antonym--> Known <--Antonym--> Unknown <--RelatedTo--> Experiment 
Contractor --DerivedFrom--> Contract <--Synonym--> Take --IsA--> Use <--Synonym--> Occupy 