Related is related to Culture. Culture is related to Characteristic. Characteristic is part of Nature. Nature is related to Pretty. 
Due is related to Pay. Clean requires Pay. Clean is the opposite of Soap. 
Related <--RelatedTo--> Culture <--RelatedTo--> Characteristic --PartOf--> Nature <--RelatedTo--> Pretty 
Due <--RelatedTo--> Pay <--HasPrerequisite-- Clean <--Antonym--> Soap 