dishabille

Etymology

From French déshabillé.

noun

1. Extreme casual or disorderly dress, for example, with the shirt-tail out, sleeves unbuttoned, etc.
   A little after 3:15 o’clock yesterday afternoon a stream of people, hatless, coatless, some in an even worse state of dishabille rushed down the stairs or to the elevators of every one of the downtown buildings and onto the streets, their faces showing every sign of terror. 1891, Seattle Post-Intelligencer
2. A loose, negligent dress.
   She wore a dishabille of mignonette-green silk and bead-diapered head-dress that added several inches to her height […] 1919, Ronald Firbank, Valmouth, Duckworth, hardback edition, page 44