Italian is a type of Person. Spy is a type of Person. Spy entails/necessarily involves Investigate. Invest is etymologically related to Investigate. 
Inner is related to Voice. Voice is related to Function. Function is related to Tide. Tide is related to Wave. 
Italian --IsA--> Person <--IsA-- Spy --Entails--> Investigate <--EtymologicallyRelatedTo-- Invest 
Inner <--RelatedTo--> Voice <--RelatedTo--> Function <--RelatedTo--> Tide <--RelatedTo--> Wave 