A detour is a path taken that goes out of the way of your usual path. Detours are usually set up when there is some obstacle and there needs to be a way around it.
Used as a verb, it simply means you are taking a detour, for example "I am going to detour past the shops on my way home".
Furniture is the name collectively used for items like tables, chairs, beds etc that you find inside your house. Furniture is generally something that you use, but some pieces of furniture are there only for decoration.
Something is obscure if it is unclear or uncertain. Something obscured cannot easily be seen or understood.
The lamp post in the picture is obscured from view.
Something is pure if it is made up of all the one kind of thing, with nothing different. Something pure has no contaminations or anything added.
The rose in the picture is pure white.