Threat is a synonym of Terror. Terror is related to Fear. Fear is the Key. Key is a type of Button. 
Beautiful is the opposite of Weak. Week is etymologically related to Weak. 
Threat <--Synonym--> Terror <--RelatedTo--> Fear --DefinedAs--> Key --IsA--> Button 
Beautiful <--Antonym--> Weak <--EtymologicallyRelatedTo-- Week 