Sexy is a type of Book. Book is related to Very. Very is related to Safe. Safe is the opposite of Danger. 
Fire is related to Treaty. Treaty is related to Contract. Contract is a synonym of Collapse. Collapse is a synonym of Crash. 
Sexy --IsA--> Book <--RelatedTo--> Very <--RelatedTo--> Safe <--Antonym--> Danger 
Fire <--RelatedTo--> Treaty <--RelatedTo--> Contract <--Synonym--> Collapse <--Synonym--> Crash 