Peak is related to Hill. Hill is related to Natural. Natural is related to Stone. Stone is related to Smooth. 
you would Hug because Sad. Sad is the opposite of Joy. Joy is related to Play. 
Peak <--RelatedTo--> Hill <--RelatedTo--> Natural <--RelatedTo--> Stone <--RelatedTo--> Smooth 
Hug --MotivatedByGoal--> Sad <--Antonym--> Joy <--RelatedTo--> Play 