Simple is related to Ordinary. Ordinary is a synonym of Plain. Plain is related to Obvious. Obvious is a synonym of Evident. 
Massive is a synonym of Significant. Significant is a synonym of Meaning. 
Simple <--RelatedTo--> Ordinary <--Synonym--> Plain <--RelatedTo--> Obvious <--Synonym--> Evident 
Massive <--Synonym--> Significant <--Synonym--> Meaning 