Enforce is a synonym of Nerve. Nerve is a synonym of Encourage. Encourage is the opposite of Discourage. Discourage is the opposite of Recommend. 
Arrow can be used for Hit. Shell is a type of Hit. Shell is related to Gasoline. Gasoline is derived from Gas. 
Enforce <--Synonym--> Nerve <--Synonym--> Encourage <--Antonym--> Discourage <--Antonym--> Recommend 
Arrow --UsedFor--> Hit <--IsA-- Shell <--RelatedTo--> Gasoline --DerivedFrom--> Gas 