Culey is a derivative of culo, which is an ass. but has the connotation of a bit of a woman's vagina as seen from behind. It has nothing to do with being stupid. It's more like punk asshole, or punkass. Culey is a derivative of Kool Aid, so it doesn't sound as bad as culo when you say it.
Synonyms of culey o kuley are ojete putio
"Ese tipo es puro culey."
