'underdress' definitions:

Dress without sufficient warmth; "She was underdressed for the hiking trip and suffered hypothermia" [ant: overclothe, overdress]

Dress informally and casually; "On Fridays, employees can underdress" [syn: dress down, underdress] [ant: attire, deck out, deck up, dress up, fancy up, fig out, fig up, get up, gussy up, overdress, prink, rig out, tog out, tog up, trick out, trick up]