Overcome is a synonym of Overwhelm. Kill is a type of Overwhelm. Kill is related to Violent. 
Ban is the opposite of Permit. Permit is related to Admit. Admit is related to Guilty. 
Overcome <--Synonym--> Overwhelm <--IsA-- Kill <--RelatedTo--> Violent 
Ban <--Antonym--> Permit <--RelatedTo--> Admit <--RelatedTo--> Guilty 