Overwhelming is a form of Overwhelm. Overwhelming is a synonym of Massive. Massive is similar to Solid. Solid is similar to Serious. 
Assume is a synonym of Undertake. Undertake is a type of Confront. 
Overwhelm <--FormOf-- Overwhelming <--Synonym--> Massive <--SimilarTo--> Solid <--SimilarTo--> Serious 
Assume <--Synonym--> Undertake --IsA--> Confront 