Fashion is related to Look. Look is related to Action. Economy is a type of Action. Economy is a type of Efficiency. 
Knock is a synonym of Tap. you are likely to find Tap in/at/on Bar. 
Fashion <--RelatedTo--> Look <--RelatedTo--> Action <--IsA-- Economy --IsA--> Efficiency 
Knock <--Synonym--> Tap --AtLocation--> Bar 