Client is a synonym of Buyer. Buyer is the opposite of Merchant. Merchant is a synonym of Dealer. 
Soft is a synonym of Quiet. Quiet is related to Call. Call is related to Color. Color is related to Part. 
Client <--Synonym--> Buyer <--Antonym--> Merchant <--Synonym--> Dealer 
Soft <--Synonym--> Quiet <--RelatedTo--> Call <--RelatedTo--> Color <--RelatedTo--> Part 