Complete shade? If it would get some sun, @ how many hours?

How many years are you willing to wait for the planting to provide privacy?

Certain Yews would work eventually.

Check out Tradewinds Bamboo web site and their Mountain Bamboo section. These are for the most part clumpers, I have had several different species and in the sixteen years I had them, they only spread out in about 3.5 feet diameter circle. The Asia genus, Fargesia has a lot of species that tolerate shade and meet your demand. The American genus has a few that meet your requirements. If you don't have a local bamboo nursery nearby, Tradewinds Bamboo is real good at packing and shipping bamboos in a timely matter.

A photo of the space if possible would help get us.

Ilex crenata 'Sky Pencil'. But doesn't grow overly fast so you will need a good sized one initially.

Bamboo can be invasive. Your plant choice is affected by where you live, so knowing your general location or USDA zone would help.

Clumping bamboo is NOT invasive. And can make an excellent evergreen screening plant in tight, narrow situations. It is also shade tolerant and quite cold hardy.......zone 6 for any Fargesia species and some will grow in zone 5.

This might be the extent of the sun. Looking straight ahead is east. The house on the right is ours. Notice the opposing dining area windows?? Ugh. And we also need to be able to walk by. The spigot for water is right there.

This is in Seattle, zone 8

Wow, that is tricky. I would for sure talk to upur neighbor as whatever you do will impact them and agreeing on a solution together is a good idea.

is the distance between the windows 2 feet? How far from your home is,the property line?

The fence is on the property line. It's hard to tell in this photo, but they have as much room on their side of the fence. Whatever we do, it needs to be without their consultation.

Yeah, I know it's super tricky. Window boxes are lovely, but I think would only serve as something pretty, not screening. We have shades...I don't want to keep them closed all the time. Actually ours stay open and neighbors close theirs. Still tho, it's just weird that we can see into each other's homes.

Why wouldn’t you just put a blind or draperies on the window interior so that no one can see in? I can’t imagine that you would want to look in their window either.

I don't like to have the shades closed all the time. Ours are open, our neighbors keep theirs closed. I'd rather look out and see greenery. We got tall trellises to grow vines. Now just need to figure out which vines!

Be sure to leave room for structural maintenance and repair access.

Try star jasmine, it likes shade and - unlike the much overused evergreen clematis for instance - doesn't shoot out long rapid growing stems that quickly get away from you. Or have large leaves that produce a coarse, often overbearing texture.

There are plantings of star jasmine all over Seattle and all independent outlets in the area stock it.

The only significant drawback to planting this choice this far north is it being hardy to something like 15 degrees F. But Cliff Mass thinks the local winters have gotten warmer.

Also star jasmine seems to have a problem with conspicuous discoloration of the leaves in full hot sun planting positions. But it wouldn't be subjected to that in your situation.

Aucuba is an excellent shade loving evergreen that will grow to 6 to 10, but will require some pruning to stay at 2 to 4 feet.

https://www.google.com/search?q=aucuba+japonica&rlz=1C1BLWB_enUS612US612&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi44OuJgMrcAhWL7VMKHV5FDn8Q_AUICigB&biw=1280&bih=891#imgrc=wuhpzb7NfnhqkM:

It's one of my favs.

I like the star Jasmine suggestion.

If plants don’t work - I'd be getting vinyl that looks like etched glass to let light in while blurring the view.. https://www.uscutter.com/Oracal-8810-Frosted-Glass?view_all 

Thank you for all your ideas! We installed some 8' trellises, 20' worth. And planted one Star Jasmine and one Cathedral Gem Sausage vine, recommended by someone at the nursery. Hopefully they will be happy and grow quickly.