The Collaborative International Dictionary of English v.0.48:

Guimpe \Guimpe\, n. [F. See 2d Gimp.]
   1. A kind of short blouse or chemisette, worn under a
      low-necked dress such as a jumper or pinafore. [WordNet
      sense 2]
      [Webster 1913 Suppl.]

   2. a piece of starched cloth covering the shoulders of a
      nun's habit. [WordNet sense 1]
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

guimpe
    n 1: a piece of starched cloth covering the shoulders of a nun's
         habit
    2: a short blouse with sleeves that is worn under a jumper or
       pinafore dress