Serious is the opposite of Play. Breath is a type of Play. Breath is related to Function. Function is a synonym of Serve. 
Brick is related to House. House is related to Shed. 
Serious <--Antonym--> Play <--IsA-- Breath <--RelatedTo--> Function <--Synonym--> Serve 
Brick <--RelatedTo--> House <--RelatedTo--> Shed 