Current is related to Description. Description is related to Excellent. 
Purpose is a synonym of Effect. Effect is related to Calm. Calm is the opposite of Wave. Wave is related to Permanent. 
Current <--RelatedTo--> Description <--RelatedTo--> Excellent 
Purpose <--Synonym--> Effect <--RelatedTo--> Calm <--Antonym--> Wave <--RelatedTo--> Permanent 