dress shield
noun
1.
a fabric or plastic pad for attaching to the inside of the underarm of a woman's garment to protect the garment from being soiled by perspiration.
Also called
shield
.
Origin
1880-85
British Dictionary definitions for
dress shield
dress shield
noun
1.
a fabric pad worn under the armpits or attached to the armhole of a garment to prevent sweat from showing on or staining the clothing