Background is the opposite of Prominent. Prominent is a synonym of Outstanding. Outstanding is a synonym of Great. Great is the opposite of Little. 
Assert is a synonym of Insist. Insist is a synonym of Demand. Demand is related to String. String is related to Loop. 
Background <--Antonym--> Prominent <--Synonym--> Outstanding <--Synonym--> Great <--Antonym--> Little 
Assert <--Synonym--> Insist <--Synonym--> Demand <--RelatedTo--> String <--RelatedTo--> Loop 