To disturb the normal order or function of something, or to make someone mentally unstable.
From Old French 'déranger' (de- + ranger, meaning 'to arrange' or 'to put in order'). The prefix 'de-' negates, so literally means 'to un-arrange.' It entered English in the 17th century with both physical and psychological meanings.
This word is like the opposite of 'arrange'—while arranging means putting things in perfect order, deranging means taking that careful order and destroying it, which is why it's used both for messed-up rooms and messed-up minds!
Complete word intelligence in one call. Free tier — 50 lookups/day.