Hurricane is related to Rain. Rain is a different concept from Dry. Drug is etymologically related to Dry. Drug is related to Tobacco. 
Prisoner is related to Hostage. 
Hurricane <--RelatedTo--> Rain <--DistinctFrom--> Dry <--EtymologicallyRelatedTo-- Drug <--RelatedTo--> Tobacco 
Prisoner <--RelatedTo--> Hostage 