A bustier is an undergarment most often worn by women. It is wrapped around the waist - above the hips and over the lower ribs - and usually is fastened by hooks or ties.
The bustier has bra cups, often demi- style and comes with or without straps.
The purpose is to streamline the waist and support the bust, by means of 'bones' and lace.
The bustier, though originally intended to be worn under clothing has occasionally made it into fashion as outerwear.
These days however, the bustier is best worn under a formfitting or strapless dress and although its function is to smooth and uplift, it is best worn on women who don't need it - as on anyone else excruciating pain is the only result.