crackbrain
Someone who is wacky or crazy. There's a guy on our corner who shouts about the end of the world; I think he's a crackbrain.
crackbrained
Wacky or crazy. There's a guy on our corner who shouts about the end of the world; I think he's a little crackbrained. Oh please, that'll never work—it's a crackbrained idea.
crackbrain
n. a fool; a stupid oaf. Did you hear about the crackbrain who said he found part of the sky floating in the lake?
crackbrained
mod. stupid; ridiculous. I’ve heard enough of your crackbrained schemes.