I believe there is evidence both for and against the idea that the characters in Get Out are zombies. They are not like a typical Romero zombie for sure but there are several things that would suggest the creatures are indeed a zombie.
First, they could be considered to be reanimated, as the host now occupying the body has “died” and is reanimated in the new body. They also appear to walk and talk in a stilted or dreamlike way, similar to the low cognition seen in zombies.
On the opposite end of the debate, the creatures appear not to be zombies. Firstly, the host themselves is not dead; they are simply trapped in the subconscious of the person. The creatures are also not attacking humans and trying to eat brains as a “typical” zombie would. Although they do talk and walk differently, the creatures do not stumble around as drastically as most zombies.
I personally would not call the creatures in Get Out zombies as I do not consider them a typical “Romero” zombie. However, if we go back to the original Hatian zonbi, then the creatures are closer to that definition of a zombie as those zombies are simply brainless people that are not flesh eating monsters. I would still consider the creatures not to be zombies even by that definition as the hosts are not dead themselves.