From Longman Dictionary of Contemporary Englishempty-headedˌempty-ˈheaded adjective informal STUPID/NOT SENSIBLEsilly and not intelligent
Examples from the Corpus
empty-headed• After all his empty-headed bimbos, he found he liked having a woman around him who demanded a bit of respect.• Nicola was not just a simpering and empty-headed blonde with a pleasant voice.• You with all your ridiculing of academic art and empty-headed Venuses? 