A vain or superficial person (sem conteúdo), or a simple-minded one.
And other ways....
Conversely, and back to the crux of the matter...here you go:
Deep and intelligent. (as opposed to dumb and shallow). **
Someone on the know.
Somebody on the ball.
An intellectual person.
Someone that is bright and exciting.
One that thinks out the box.
Someone that is bright/a very smart person (smart people).
He/she is deep and sophisticated (has a sophisticated mind.)
She/he got a brain, not only muscles (or is not just a pretty face).
She/he is a girl/guy of many talents (not just a pretty face).
...are some probable ways to mean that, of course, said in different circumstances it may work or not. Context is everything.
**someone interesting/deep and intelligent is really a "bombril" (a thousand uses indeed), because it hints you are saying some appreciatively. And at the same time, it have a good ring to it. Since it makes you think about social and intellectual skills, sort of.
Anyway, it´s a guess of mine, others may think all them do the same effect.