empty-headed 
adjective
Unintelligent and foolish: an empty-headed bimbo...
- In many games on the market today, women are portrayed as empty-headed bimbos that need saving, all the while wearing little more than a handkerchief.
- In this episode the merry band of plastic surgeons valiantly strives to rescue empty-headed bimbos who want to ‘look 17 for ever‘.
- I have been around them enough to know that your mother is a manipulative gossip, and your sisters are empty-headed and vapid.
Synonyms
stupid, unintelligent, idiotic, foolish, silly, brainless, half-witted, witless, vacuous, vapid, hare-brained, feather-brained, birdbrained, pea-brained, scatterbrained, scatty, giddy, skittish, flighty, frivolous, thoughtless
informal dumb, dense, dim, airheaded, brain-dead, dippy, dizzy, dopey, dozy, batty, dotty, screwy, soft in the head, slow on the uptake
British informal daft, not the full shilling, dappy
North American informal ditzy, dumb-ass