Balanced is a form of Balance. Balance is related to Justice. Justice is related to Scale. Scale is related to Size. 
Unable is the opposite of Able. Able is a synonym of Equal. Equal is a synonym of Touch. Touch is related to Physical. 
Balanced --FormOf--> Balance <--RelatedTo--> Justice <--RelatedTo--> Scale <--RelatedTo--> Size 
Unable <--Antonym--> Able <--Synonym--> Equal <--Synonym--> Touch <--RelatedTo--> Physical 