Confuse is the opposite of Distinguish. Distinguish is a synonym of Difference. Difference is the opposite of Identity. Identity is etymologically related to Identical. 
Hole can be used for Water. Hole can be Dark. 
Confuse <--Antonym--> Distinguish <--Synonym--> Difference <--Antonym--> Identity --EtymologicallyRelatedTo--> Identical 
Water <--UsedFor-- Hole --HasProperty--> Dark 