feather-brained

It means she is silly and emtpy - headed.

Savvy

'Featherbrained' (not hyphenated)

...also means 'light-headed', as in light as a feather...perhaps related to 'birdbrain', meaning 'silly' or 'stupid'.

Would it also translate to someone being hollow?

Savvy

"She is a featherbrained girl."

I don't think it would mean "hollow", Savvy. I've always thought of it as a "pillow" metaphor: her brain is stuffed with light silly thoughts, as a pillow is stuffed with feathers.

MrP

There's also "pea-brained", which I assume, implies a brain as small as a pea?

I'm afraid so...with a sense of something very small rattling round in a very large space...

MrP

I like your sense of humour MrP, maybe we should come up with a new word :

He is a stuffed-pillow. (Why does it always have to be a she,anyway?)

Then again calling a man, stuffed pillow makes me think of...err..

Savvy

SavvysavzThen again calling a man, stuffed pillow makes me think of...err..

Indeed.