A preppy, semi-dim-witted girl often seen in clusters (ie. Brendies.) Brendies often come from wealthy families and are typically naive to the ways of the world, men, and suffering of other people. A Brendy can usually be marked by blonde hair, squeaky voice, short skirts, over-sized handbags, small dogs in purses, far-away expressions, pink clothing/accessories etc. etc. etc. (I'm sure you get the gist.) though these characteristics are not always present, chances are you will still know a Brendy when you see one.
"Ugh! It's another Brendy."
"I can't stand those Brendy girls."