Subsidy is the opposite of Tax. Tax is related to Extra. Extra is related to Additional. Additional is a synonym of Other. 
Horse is related to Draft. Draft is a type of Regulator. Regulator is a synonym of Governor. Governor is a type of Executive. 
Subsidy <--Antonym--> Tax <--RelatedTo--> Extra <--RelatedTo--> Additional <--Synonym--> Other 
Horse <--RelatedTo--> Draft --IsA--> Regulator <--Synonym--> Governor --IsA--> Executive 