Reason is a synonym of Understanding. Understanding is related to Care. Care is a synonym of Worry. 
Terrorist is a type of Criminal. Criminal is related to Crime. Crime is related to Illegal. Illegal is the opposite of Legal. 
Reason <--Synonym--> Understanding <--RelatedTo--> Care <--Synonym--> Worry 
Terrorist --IsA--> Criminal <--RelatedTo--> Crime <--RelatedTo--> Illegal <--Antonym--> Legal 