Definitionbosom wearing (and looking good in) a tight-fitting sweater.
(1) Charles Panati. Sexy Origins and Intimate Things (1998): ' Lana Turner, in a sharp, cone-shaped bra - the hard cones achieved by tight circular stitching - became Americas "Sweater Girl" launching an entirely new look for women. A tight sweater, which accentuated the pointed breasts, became American womens - and mens - favorite topwear.'
(2) Rosalie Maggio. Dictionary of Bias-Free Usage (1991): ' "Sweater girl" implies a great deal more than what the woman looks like: it also hints at her lifestyle and her intelligence, all on the basis of how she looks in a sweater. Avoid making an issue of woman's physical appearance when this is so rarely done for men.'