Plain is a synonym of Bare. Bare is the opposite of Decorate. Deck is a type of Decorate. Deck is related to Wooden. 
Receive is related to Believe. Believe is related to Philosophy. Philosophy is related to Thought. Thought is related to Cognitive. 
Plain <--Synonym--> Bare <--Antonym--> Decorate <--IsA-- Deck <--RelatedTo--> Wooden 
Receive <--RelatedTo--> Believe <--RelatedTo--> Philosophy <--RelatedTo--> Thought <--RelatedTo--> Cognitive 