Facepalmist
A facepalmist is a human who is so dumb it hurts. They make you slap your face so hard you probably break it. They are not just dumb, they are dumb all the time and in the worst ways possible.
My cousin asked if the sun was a lightbulb. I facepalmed so hard I got a headache.
My teacher said, 'Why do you think the sky is blue? Because it’s a mood.' I facepalmed so much I got a migraine.
My dog barked at a cloud. I facepalmed and cried.