I recently redid one of our guest bathrooms this past fall and bought two of the shower curtains shown below and used as window curtains. I used curtain rings w/ clips to put on my existing curtain rods. These curtains come in different colorways and different sizes. I like Wayfair because they do have a lot of items to look at and they ship fast. I have never been unhappy w/ anything I purchased from them.
I did look locally and online, but these were the closest to what I was looking for, color wise and the material is quite hefty. My husband went outside the window to check to see if body shapes were visible at night w/ light on and these blocked out any body shape. So yay to that! I did have to iron (steam), which took all of 5 minutes per curtain.

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