Guilt is a synonym of Regret. Regret is related to Mistake. 
Concept is related to Ideal. Ideal is related to Theory. Theory is related to Fundamental. Fundamental is a synonym of Radical. 
Guilt <--Synonym--> Regret <--RelatedTo--> Mistake 
Concept <--RelatedTo--> Ideal <--RelatedTo--> Theory <--RelatedTo--> Fundamental <--Synonym--> Radical 