Opt is the opposite of Join. Join is related to Holy. Holy is related to Minister. Minister is related to Religion. 
Chest is related to Back. Back is a different concept from Side. 
Opt <--Antonym--> Join <--RelatedTo--> Holy <--RelatedTo--> Minister <--RelatedTo--> Religion 
Chest <--RelatedTo--> Back <--DistinctFrom--> Side 