Argue is a synonym of Contend. Contend is a synonym of Contest. Contest is related to Fight. Engage is a type of Fight. 
Guess is related to Question. Question is a synonym of Doubt. 
Argue <--Synonym--> Contend <--Synonym--> Contest <--RelatedTo--> Fight <--IsA-- Engage 
Guess <--RelatedTo--> Question <--Synonym--> Doubt 