Merchant is related to Occupation. Occupation is related to Farmer. Farmer is related to Crop. Crop is related to Commodity. 
Ocean is the opposite of Land. Land is related to Waste. Waste is related to Dump. 
Merchant <--RelatedTo--> Occupation <--RelatedTo--> Farmer <--RelatedTo--> Crop <--RelatedTo--> Commodity 
Ocean <--Antonym--> Land <--RelatedTo--> Waste <--RelatedTo--> Dump 