Word or phrase for a woman who shows up at events in gaudy outfits, garish make-up, and excessive jewelry?

Such person is usually - but not necessarily - upper-middle class.

I'm looking for a noun or a noun-phrase but the words I've found so far (unpolished, inelegant, gauche, etc.) are adjectives and/or don't fit what I'm looking for.

EDIT

This noun or noun-phrase...

• is more likely to be used by women when gossiping. ("Did you see that .... at the meeting yesterday? Yeah, I did. Some people just don't know how ridiculous they can get.)
• isn't related to promiscuity or prostitution.

If the woman is a socialite, her picture will be displayed in newspapers and magazines and she will be a laughingstock..

Solution 1:

It's often been said that beauty is in the eye of the beholder. What one person finds trashy, slutty, tarty, cheap or tacky-looking in a woman; another sees a woman who oozes self-confidence, style, glamour and sex-appeal.

A woman who has put on a gaudy outfit could be described as being dressed to the nines; gussied, fancied or dolled up; sassy; and looking to have fun. If she is dressed provocatively (gaudy outfits), wears expensive cosmetics (garish makeup), and prefers costume jewelry (excessive jewelry) to that of gold and platinum, she is said to be dressed to kill.

She can be called a man-eater; a seductress; a flirt; a femme fatale or just a socialite

Socialite
She lives in a paradise of a mansion, usually in California, or a penthouse in Manhattan. You might find her hanging out at various social events, with a glass of champagne in her hand. Often she doesn't have a job, but sometimes she can be working in a high-end job, such as that of a celebrity publicist, which nets her a very high salary. (...) Can also be prone to Conspicuous Consumption, especially jewels, fancy dresses, and furs.

Alternatively, if she is young and has recently come into money she might be termed as

Nouveau Riche
The Nouveau Riche are characterized as rude and tasteless, and frequently contrasted with the refined manners of aristocratic Old Money characters. (...) If American, expect them to be Hollywood California people with bleach-blonde Valley Girl daughters, slovenly white trash who won either the lottery or a big-time settlement ... If black, expect a flashy character from a Glam Rap video. (...) Common accessories for this class include fur coats, gaudy jewelry, obnoxiously color-coordinated suits, and gold teeth.

Source: TV Tropes

Solution 2:

If the lady in question is well past her forties, and used to be a highly attractive and courted woman in the past, she might dress provocatively and wear heavy makeup in order to recapture her former glory. Such a woman is often derogatorily called mutton dressed (up) as lamb. in British English.

an offensive way of saying that a woman is dressed in a style that is more suitable for a much younger woman