robe vague

CONT: Robe-sac : robe qui n'est pas ajustée à la taille.
OBS: Vague : Qui n'est pas ajusté, serré. - Flou, lâche.

CONT: In the years since the New Look, several silhouettes have flourished for a time -- the sack dress, the miniskirt, the maxi among them. But the phenomenon of the New Look has yet to be duplicated.
CONT: Dior's Decade - Women'sFashions of the 1950s. Silhouette ... silhouettes were more varied. On these outlines, women wore a trim bodice and very full knee-length skirt, or a fitted short, boxy jacket or blouse with a pencil-straight skirt. One style that hid all the rest, literally, was the cocoon-like sacque dress and coat, which fitted the shoulders and bloomed at the waist and hips.