Expensive is the opposite of Afford. Afford is a synonym of Communicate. Write is a type of Communicate. 
Mental is related to Slip. Slip is related to Loose. Loose is a synonym of Liberal. Liberal is the opposite of Conservative. 
Expensive <--Antonym--> Afford <--Synonym--> Communicate <--IsA-- Write 
Mental <--RelatedTo--> Slip <--RelatedTo--> Loose <--Synonym--> Liberal <--Antonym--> Conservative 