juste-au-corps

A tight, knee-length men's coat worn in the late 17th and early 18th century.

Under a full dress coat […] appeared a waistcoat of glod-flowered brocade, the flaps reaching to his knees, and made, I am persuaded, in the reign of Louis ci-devant le Grand.—What appeared of his breeches, under this magnificent juste au-corps, was of red velveret, forming a happy contrast to a pair of black worsted stockings.

A tight women's riding coat of the late 17th and early 18th century.

Any tight-fitting garment, specifically a coat or waistcoat, of the second half of the 17th century.