fashion whore
A preachy know it all under a skin of designer clothing. Criticizes everything she considers "out of style" or "tacky". Also turns up her nose at anything cheaper than American Eagle. Doesn't realize that what one wears is a personal thing, and wearing what you like is better than following every trend.

People who are truly fashion savvy respect each other's unique style.
"Eh-mah-gawd, look at that geek" exclaimed Gina the fashion whore as she slipped on her Dior heels and checked her perfectly fit Sevens for any trace of lint.
"Why is she wearing a pink miniskirt over jeans? That is just so tacky! And black hair is totally OUT! C'mon girls, let's give her a makeover."

"Eww I saw that shirt at Aeropostale the other day! Such a gross cheap store," agreed her airhead follower Tina.