Walk is the opposite of Sit. Sit is related to Motion. Pursuit is a type of Motion. Pursuit is related to Game. 
Speculation is a synonym of Guess. Guess is related to Hypothesis. 
Walk <--Antonym--> Sit <--RelatedTo--> Motion <--IsA-- Pursuit <--RelatedTo--> Game 
Speculation <--Synonym--> Guess <--RelatedTo--> Hypothesis 