Quiet is the opposite of Loud. Loud is a different concept from Silence. Silence is related to Condition. Condition is a type of Premise. 
Legal is related to Permit. Permit is related to Document. Platform is a type of Document. Platform is a synonym of Sidewalk. 
Quiet <--Antonym--> Loud <--DistinctFrom--> Silence <--RelatedTo--> Condition --IsA--> Premise 
Legal <--RelatedTo--> Permit <--RelatedTo--> Document <--IsA-- Platform <--Synonym--> Sidewalk 