Not as stupid as being dumb, but still less than normal intelligence. The only thing that comes out of their mouth is dumb shit, and if they think of somethingsmart, they pulled it out of their ass.
Guy: Dude, go get that bitch's number over there.
Headass: No man, she's probably trans.
Guy: You headass, mendon't have asses like that! I'll get her myself if you gonna be that dumb.