Enemy is related to Opponent. Opponent is a synonym of Opposition. Opposition is the opposite of Support. Support is related to Peer. 
Doctor is related to Illness. Illness is related to Heal. Heal is a synonym of Recover. 
Enemy <--RelatedTo--> Opponent <--Synonym--> Opposition <--Antonym--> Support <--RelatedTo--> Peer 
Doctor <--RelatedTo--> Illness <--RelatedTo--> Heal <--Synonym--> Recover 