Grandfather is related to Old. Old is related to Shoe. Shoe is related to Thick. Thick is similar to Heavy. 
Divorce is related to Separation. Wall can be used for Separation. 
Grandfather <--RelatedTo--> Old <--RelatedTo--> Shoe <--RelatedTo--> Thick <--SimilarTo--> Heavy 
Divorce <--RelatedTo--> Separation <--UsedFor-- Wall 