Explain is related to Justify. Legitimate is a type of Justify. Legitimate is a synonym of Logical. Logical is similar to Formal. 
Pot is related to Illegal. Illegal is the opposite of Citizen. Citizen is related to Voter. 
Explain <--RelatedTo--> Justify <--IsA-- Legitimate <--Synonym--> Logical <--SimilarTo--> Formal 
Pot <--RelatedTo--> Illegal <--Antonym--> Citizen <--RelatedTo--> Voter 