Simple is a synonym of Plain. Plain is a synonym of Apparent. Apparent is a synonym of Clear. 
Total is a synonym of Absolute. Absolute is related to Certain. Certain is the opposite of Uncertain. 
Simple <--Synonym--> Plain <--Synonym--> Apparent <--Synonym--> Clear 
Total <--Synonym--> Absolute <--RelatedTo--> Certain <--Antonym--> Uncertain 