Wiktionary
n. 1 (context pejorative English) A female preoccupied with appearance while neglecting intellectual pursuits, (often taken to extremes); a blonde bimbo. 2 By extension, infrequently used to refer to blond males.
Usage examples of "dumb blonde".
It was Longarm who suggested, out in the hall, that the prosecution might explain the facts of life to Miss Elvira Carson, the beautiful dumb blonde.
The whole point about the Mistress is she's not just a dumb blonde, right?
But it's sort of soothing to know Trisha was only a dumb blonde after all.
He had met her only once before, at a nightclub in the Cross where Danny had thrown a party, and she had sat across from him hardly saying a word all night, playing the dumb blonde except that she wasn't blonde.
She was a classic dumb blonde - the Mayor picked his secretaries for looks rather than character - and she was rather flustered.